diff --git a/src/main/java/edu/handong/csee/histudy/controller/AdminController.java b/src/main/java/edu/handong/csee/histudy/controller/AdminController.java
index 2ec034a..e98e5c0 100644
--- a/src/main/java/edu/handong/csee/histudy/controller/AdminController.java
+++ b/src/main/java/edu/handong/csee/histudy/controller/AdminController.java
@@ -56,7 +56,6 @@ public ResponseEntity<TeamReportDto> getTeamReports(
       @RequestAttribute Claims claims) {
     if (Role.isAuthorized(claims, Role.ADMIN)) {
       TeamReportDto res = teamService.getTeamReports(id, claims.getSubject());
-
       return ResponseEntity.ok(res);
     }
     throw new ForbiddenException();
@@ -111,6 +110,7 @@ public ResponseEntity<List<UserDto.UserInfo>> getUnmatchedUsers(@RequestAttribut
   public void deleteForm(@RequestParam String sid, @RequestAttribute Claims claims) {
     if (Role.isAuthorized(claims, Role.ADMIN)) {
       userService.deleteUserForm(sid);
+      return;
     }
     throw new ForbiddenException();
   }
@@ -120,6 +120,7 @@ public void deleteForm(@RequestParam String sid, @RequestAttribute Claims claims
   public void editUser(@RequestBody UserDto.UserEdit form, @RequestAttribute Claims claims) {
     if (Role.isAuthorized(claims, Role.ADMIN)) {
       userService.editUser(form);
+      return;
     }
     throw new ForbiddenException();
   }
diff --git a/src/main/java/edu/handong/csee/histudy/controller/TeamController.java b/src/main/java/edu/handong/csee/histudy/controller/TeamController.java
index dd00bc8..f9062d5 100644
--- a/src/main/java/edu/handong/csee/histudy/controller/TeamController.java
+++ b/src/main/java/edu/handong/csee/histudy/controller/TeamController.java
@@ -1,16 +1,11 @@
 package edu.handong.csee.histudy.controller;
 
 import edu.handong.csee.histudy.controller.form.ReportForm;
-import edu.handong.csee.histudy.domain.AcademicTerm;
 import edu.handong.csee.histudy.domain.Role;
-import edu.handong.csee.histudy.domain.StudyGroup;
-import edu.handong.csee.histudy.domain.User;
 import edu.handong.csee.histudy.dto.CourseDto;
 import edu.handong.csee.histudy.dto.ReportDto;
 import edu.handong.csee.histudy.dto.UserDto;
 import edu.handong.csee.histudy.exception.ForbiddenException;
-import edu.handong.csee.histudy.exception.NoCurrentTermFoundException;
-import edu.handong.csee.histudy.exception.UserNotFoundException;
 import edu.handong.csee.histudy.repository.AcademicTermRepository;
 import edu.handong.csee.histudy.repository.StudyGroupRepository;
 import edu.handong.csee.histudy.repository.UserRepository;
@@ -156,18 +151,7 @@ public ResponseEntity<Map<String, String>> uploadImage(
       @RequestParam MultipartFile image,
       @RequestAttribute Claims claims) {
     if (Role.isAuthorized(claims, Role.MEMBER)) {
-      AcademicTerm currentTerm =
-          academicTermRepository
-              .findCurrentSemester()
-              .orElseThrow(NoCurrentTermFoundException::new);
-      User user =
-          userRepository
-              .findUserByEmail(claims.getSubject())
-              .orElseThrow(UserNotFoundException::new);
-      StudyGroup studyGroup =
-          studyGroupRepository.findByUserAndTerm(user, currentTerm).orElseThrow();
-
-      String filename = imageService.getImagePaths(image, studyGroup.getTag(), reportIdOr);
+      String filename = imageService.getImagePaths(claims.getSubject(), image, reportIdOr);
       Map<String, String> response = Map.of("imagePath", filename);
       return ResponseEntity.ok(response);
     }
diff --git a/src/main/java/edu/handong/csee/histudy/domain/StudyApplicant.java b/src/main/java/edu/handong/csee/histudy/domain/StudyApplicant.java
index 719d70f..82800f3 100644
--- a/src/main/java/edu/handong/csee/histudy/domain/StudyApplicant.java
+++ b/src/main/java/edu/handong/csee/histudy/domain/StudyApplicant.java
@@ -26,7 +26,7 @@ public class StudyApplicant extends BaseTime {
   @JoinColumn(name = "user_id")
   private User user;
 
-  @ManyToOne(fetch = FetchType.LAZY)
+  @ManyToOne(fetch = FetchType.LAZY, cascade = CascadeType.PERSIST)
   @JoinColumn(name = "study_group_id")
   private StudyGroup studyGroup;
 
diff --git a/src/main/java/edu/handong/csee/histudy/domain/StudyGroup.java b/src/main/java/edu/handong/csee/histudy/domain/StudyGroup.java
index b9b61d6..cc5a281 100644
--- a/src/main/java/edu/handong/csee/histudy/domain/StudyGroup.java
+++ b/src/main/java/edu/handong/csee/histudy/domain/StudyGroup.java
@@ -50,21 +50,12 @@ public static StudyGroup of(Integer tag, AcademicTerm current, List<StudyApplica
     return new StudyGroup(tag, current, applicants.toArray(StudyApplicant[]::new));
   }
 
-  public static StudyGroup of(Integer tag, AcademicTerm current) {
-    return new StudyGroup(tag, current);
-  }
-
   protected StudyGroup(Integer tag, AcademicTerm academicTerm, StudyApplicant... applicants) {
     this.tag = tag;
     this.academicTerm = academicTerm;
     assignMembers(applicants);
   }
 
-  protected StudyGroup(Integer tag, AcademicTerm academicTerm) {
-    this.tag = tag;
-    this.academicTerm = academicTerm;
-  }
-
   private List<Course> findCommonCourses(StudyApplicant... applicants) {
     if (!this.courses.isEmpty()) {
       this.courses.clear();
@@ -94,13 +85,13 @@ private List<Course> findCommonCourses(StudyApplicant... applicants) {
   public StudyGroup assignMembers(StudyApplicant... applicants) {
     Arrays.stream(applicants)
         .forEach(
-            form -> {
-              if (isInSameGroup(form)) {
+            applicant -> {
+              if (isInSameGroup(applicant)) {
                 return;
-              } else if (isAlreadyInOtherGroup(form)) {
-                form.leaveGroup();
+              } else if (isAlreadyInOtherGroup(applicant)) {
+                applicant.leaveGroup();
               }
-              GroupMember.of(this, form);
+              GroupMember.of(this, applicant);
             });
     assignCommonCourses(applicants);
     return this;
@@ -114,14 +105,15 @@ public void removeMember(User member) {
   }
 
   private boolean isAlreadyInOtherGroup(StudyApplicant applicant) {
-    return applicant != null && !applicant.getStudyGroup().equals(this);
+    return applicant.getStudyGroup() != null && !applicant.getStudyGroup().equals(this);
   }
 
   public boolean isInSameGroup(StudyApplicant applicant) {
-    return applicant != null && applicant.getStudyGroup().equals(this);
+    return applicant.getStudyGroup() != null && applicant.getStudyGroup().equals(this);
   }
 
   protected void assignCommonCourses(StudyApplicant... applicants) {
+    if (isSameMemberExact(applicants)) return;
     if (this.members.isEmpty()) {
       this.courses.clear();
       this.tag = -1;
@@ -132,6 +124,16 @@ protected void assignCommonCourses(StudyApplicant... applicants) {
         .forEach(course -> new GroupCourse(this, course));
   }
 
+  private boolean isSameMemberExact(StudyApplicant... applicants) {
+    if (this.courses.isEmpty()) {
+      return false;
+    }
+    Set<User> users =
+        Arrays.stream(applicants).map(StudyApplicant::getUser).collect(Collectors.toSet());
+    Set<User> members = this.members.stream().map(GroupMember::getUser).collect(Collectors.toSet());
+    return members.containsAll(users);
+  }
+
   private boolean isNotInGroupCourse(Course course) {
     return this.courses.stream().map(GroupCourse::getCourse).noneMatch(c -> c.equals(course));
   }
diff --git a/src/main/java/edu/handong/csee/histudy/dto/TeamDto.java b/src/main/java/edu/handong/csee/histudy/dto/TeamDto.java
index 04e6764..d5bf0e7 100644
--- a/src/main/java/edu/handong/csee/histudy/dto/TeamDto.java
+++ b/src/main/java/edu/handong/csee/histudy/dto/TeamDto.java
@@ -37,7 +37,9 @@ public TeamDto(
             .map(
                 user -> {
                   StudyApplicant applicant = applicantMap.get(user);
-                  return new UserDto.UserInfo(user, applicant);
+                  return (applicant == null)
+                      ? new UserDto.UserInfo(user)
+                      : new UserDto.UserInfo(user, applicant);
                 })
             .toList();
     this.reports = reports.size();
diff --git a/src/main/java/edu/handong/csee/histudy/dto/UserDto.java b/src/main/java/edu/handong/csee/histudy/dto/UserDto.java
index 9c0cd01..73afe72 100644
--- a/src/main/java/edu/handong/csee/histudy/dto/UserDto.java
+++ b/src/main/java/edu/handong/csee/histudy/dto/UserDto.java
@@ -1,7 +1,7 @@
 package edu.handong.csee.histudy.dto;
 
-import edu.handong.csee.histudy.domain.StudyApplicant;
 import edu.handong.csee.histudy.domain.PreferredCourse;
+import edu.handong.csee.histudy.domain.StudyApplicant;
 import edu.handong.csee.histudy.domain.StudyPartnerRequest;
 import edu.handong.csee.histudy.domain.User;
 import edu.handong.csee.histudy.jwt.JwtPair;
@@ -112,16 +112,20 @@ public UserInfo(User user, StudyApplicant applicant) {
       this.email = user.getEmail();
       this.group = (applicant.getStudyGroup() == null) ? null : applicant.getStudyGroup().getTag();
       this.friends =
-          applicant.getPartnerRequests().stream()
-              .filter(StudyPartnerRequest::isAccepted)
-              .map(StudyPartnerRequest::getReceiver)
-              .map(UserBasic::new)
-              .toList();
+          (applicant.getPartnerRequests() == null)
+              ? Collections.emptyList()
+              : applicant.getPartnerRequests().stream()
+                  .filter(StudyPartnerRequest::isAccepted)
+                  .map(StudyPartnerRequest::getReceiver)
+                  .map(UserBasic::new)
+                  .toList();
       this.courses =
-          applicant.getPreferredCourses().stream()
-              .sorted(Comparator.comparing(PreferredCourse::getPriority))
-              .map(c -> new CourseDto.BasicCourseInfo(c.getCourse()))
-              .toList();
+          (applicant.getPreferredCourses() == null)
+              ? Collections.emptyList()
+              : applicant.getPreferredCourses().stream()
+                  .sorted(Comparator.comparing(PreferredCourse::getPriority))
+                  .map(c -> new CourseDto.BasicCourseInfo(c.getCourse()))
+                  .toList();
     }
 
     public UserInfo(User user) {
diff --git a/src/main/java/edu/handong/csee/histudy/repository/StudyApplicantRepository.java b/src/main/java/edu/handong/csee/histudy/repository/StudyApplicantRepository.java
index 8377e2c..acd239c 100644
--- a/src/main/java/edu/handong/csee/histudy/repository/StudyApplicantRepository.java
+++ b/src/main/java/edu/handong/csee/histudy/repository/StudyApplicantRepository.java
@@ -15,27 +15,27 @@
 public interface StudyApplicantRepository extends JpaRepository<StudyApplicant, Long> {
 
   @Query(
-      "select s from StudyApplicant s join fetch s.partnerRequests "
-              + "where s.user = :applicant and s.academicTerm = :currentTerm")
+      "select s from StudyApplicant s left join fetch s.preferredCourses "
+          + "where s.user = :applicant and s.academicTerm = :currentTerm")
   Optional<StudyApplicant> findByUserAndTerm(User applicant, AcademicTerm currentTerm);
 
   @Query(
-      "select s from StudyApplicant s join fetch s.partnerRequests "
+      "select s from StudyApplicant s left join fetch s.preferredCourses "
           + "where s.academicTerm = :currentTerm and s.studyGroup is null")
   List<StudyApplicant> findUnassignedApplicants(AcademicTerm currentTerm);
 
   @Query(
-      "select s from StudyApplicant s join fetch s.partnerRequests "
+      "select s from StudyApplicant s join fetch s.user "
           + "where s.academicTerm = :currentTerm and s.studyGroup is not null")
   List<StudyApplicant> findAssignedApplicants(AcademicTerm currentTerm);
 
   @Query(
-      "select s from StudyApplicant s join fetch s.partnerRequests "
+      "select s from StudyApplicant s left join fetch s.preferredCourses "
           + "where s.academicTerm = :currentTerm")
   List<StudyApplicant> findAllByTerm(AcademicTerm currentTerm);
 
   @Query(
-      "select s from StudyApplicant s join fetch s.partnerRequests "
+      "select s from StudyApplicant s left join fetch s.preferredCourses "
           + "where s.studyGroup = :studyGroup")
-  List<edu.handong.csee.histudy.domain.StudyApplicant> findAllByStudyGroup(@Param("studyGroup") StudyGroup group);
+  List<StudyApplicant> findAllByStudyGroup(@Param("studyGroup") StudyGroup group);
 }
diff --git a/src/main/java/edu/handong/csee/histudy/repository/StudyGroupRepository.java b/src/main/java/edu/handong/csee/histudy/repository/StudyGroupRepository.java
index fccaf34..609c6d1 100644
--- a/src/main/java/edu/handong/csee/histudy/repository/StudyGroupRepository.java
+++ b/src/main/java/edu/handong/csee/histudy/repository/StudyGroupRepository.java
@@ -26,7 +26,9 @@ public interface StudyGroupRepository extends JpaRepository<StudyGroup, Long> {
   List<StudyGroup> findAllByAcademicTerm(@Param("academicTerm") AcademicTerm academicTerm);
 
   @Query(
-      "select s from StudyGroup s where :user member of s.members and s.academicTerm = :currentTerm")
+      "select s from StudyGroup s "
+          + "join s.members m "
+          + "where m.user = :user and s.academicTerm = :currentTerm")
   Optional<StudyGroup> findByUserAndTerm(
       @Param("user") User user, @Param("currentTerm") AcademicTerm currentTerm);
 }
diff --git a/src/main/java/edu/handong/csee/histudy/service/CourseService.java b/src/main/java/edu/handong/csee/histudy/service/CourseService.java
index 38f0933..a660030 100644
--- a/src/main/java/edu/handong/csee/histudy/service/CourseService.java
+++ b/src/main/java/edu/handong/csee/histudy/service/CourseService.java
@@ -4,11 +4,9 @@
 import edu.handong.csee.histudy.dto.CourseDto;
 import edu.handong.csee.histudy.dto.CourseIdDto;
 import edu.handong.csee.histudy.exception.NoCurrentTermFoundException;
+import edu.handong.csee.histudy.exception.StudyGroupNotFoundException;
 import edu.handong.csee.histudy.exception.UserNotFoundException;
-import edu.handong.csee.histudy.repository.AcademicTermRepository;
-import edu.handong.csee.histudy.repository.CourseRepository;
-import edu.handong.csee.histudy.repository.StudyGroupRepository;
-import edu.handong.csee.histudy.repository.UserRepository;
+import edu.handong.csee.histudy.repository.*;
 import edu.handong.csee.histudy.util.CSVResolver;
 import edu.handong.csee.histudy.util.CourseCSV;
 import java.io.IOException;
@@ -24,6 +22,7 @@ public class CourseService {
   private final UserRepository userRepository;
   private final AcademicTermRepository academicTermRepository;
   private final StudyGroupRepository studyGroupRepository;
+  private final StudyApplicantRepository studyApplicantRepository;
 
   public void readCourseCSV(MultipartFile file) throws IOException {
     CSVResolver resolver = CSVResolver.of(file.getInputStream());
@@ -65,10 +64,13 @@ public List<CourseDto.CourseInfo> getTeamCourses(String email) {
     User user = userRepository.findUserByEmail(email).orElseThrow(UserNotFoundException::new);
     AcademicTerm currentTerm =
         academicTermRepository.findCurrentSemester().orElseThrow(NoCurrentTermFoundException::new);
+    StudyGroup studyGroup =
+        studyGroupRepository
+            .findByUserAndTerm(user, currentTerm)
+            .orElseThrow(StudyGroupNotFoundException::new);
 
-    StudyGroup studyGroup = studyGroupRepository.findByUserAndTerm(user, currentTerm).orElseThrow();
-    List<Course> courses =
-        studyGroup.getCourses().stream().map(GroupCourse::getCourse).toList();
+    studyGroupRepository.findByUserAndTerm(user, currentTerm).orElseThrow();
+    List<Course> courses = studyGroup.getCourses().stream().map(GroupCourse::getCourse).toList();
 
     return courses.stream().map(CourseDto.CourseInfo::new).toList();
   }
diff --git a/src/main/java/edu/handong/csee/histudy/service/ImageService.java b/src/main/java/edu/handong/csee/histudy/service/ImageService.java
index ff73d33..e7cd209 100644
--- a/src/main/java/edu/handong/csee/histudy/service/ImageService.java
+++ b/src/main/java/edu/handong/csee/histudy/service/ImageService.java
@@ -2,10 +2,12 @@
 
 import static org.springframework.util.ResourceUtils.isUrl;
 
+import edu.handong.csee.histudy.domain.AcademicTerm;
 import edu.handong.csee.histudy.domain.ReportImage;
-import edu.handong.csee.histudy.exception.FileTransferException;
-import edu.handong.csee.histudy.exception.ReportNotFoundException;
-import edu.handong.csee.histudy.repository.StudyReportRepository;
+import edu.handong.csee.histudy.domain.StudyGroup;
+import edu.handong.csee.histudy.domain.User;
+import edu.handong.csee.histudy.exception.*;
+import edu.handong.csee.histudy.repository.*;
 import edu.handong.csee.histudy.util.ImagePathMapper;
 import edu.handong.csee.histudy.util.Utils;
 import java.io.File;
@@ -34,11 +36,24 @@ public class ImageService {
   @Value("${custom.resource.location}")
   private String imageBaseLocation;
 
+  private final AcademicTermRepository academicTermRepository;
+  private final UserRepository userRepository;
   private final StudyReportRepository studyReportRepository;
+  private final StudyApplicantRepository studyApplicantRepository;
+
   private final ImagePathMapper imagePathMapper;
+  private final StudyGroupRepository studyGroupRepository;
 
   public String getImagePaths(
-      MultipartFile imageAsFormData, Integer tag, Optional<Long> reportIdOr) {
+      String email, MultipartFile imageAsFormData, Optional<Long> reportIdOr) {
+    AcademicTerm currentTerm =
+        academicTermRepository.findCurrentSemester().orElseThrow(NoCurrentTermFoundException::new);
+    User user = userRepository.findUserByEmail(email).orElseThrow(UserNotFoundException::new);
+    StudyGroup studyGroup =
+        studyGroupRepository
+            .findByUserAndTerm(user, currentTerm)
+            .orElseThrow(StudyGroupNotFoundException::new);
+
     if (reportIdOr.isPresent()) {
       Long id = reportIdOr.get();
       Optional<String> sameResource = getSameContent(imageAsFormData, id);
@@ -58,7 +73,8 @@ public String getImagePaths(
     // e.g. 2023-2-group1-report_20230923_123456.jpg
     String pathname =
         String.format(
-            "%d-%d-group%02d-report_%s%s", year, semester, tag, formattedDateTime, extension);
+            "%d-%d-group%02d-report_%s%s",
+            year, semester, studyGroup.getTag(), formattedDateTime, extension);
     String savedImagePath = saveImage(imageAsFormData, pathname);
 
     return imagePathMapper.getFullPath(savedImagePath);
diff --git a/src/main/java/edu/handong/csee/histudy/service/TeamService.java b/src/main/java/edu/handong/csee/histudy/service/TeamService.java
index e768302..17a7840 100644
--- a/src/main/java/edu/handong/csee/histudy/service/TeamService.java
+++ b/src/main/java/edu/handong/csee/histudy/service/TeamService.java
@@ -40,20 +40,15 @@ public List<TeamDto> getTeams(String email) {
                   studyReportRepository.findAllByStudyGroupOrderByCreatedDateDesc(group);
               List<StudyApplicant> applicants = studyApplicantRepository.findAllByStudyGroup(group);
 
-              Map<User, StudyApplicant> formMap =
+              Map<User, StudyApplicant> applicantMap =
                   applicants.stream()
-                      .filter(form -> isFormRelevantToGroup(form, group))
                       .collect(Collectors.toMap(StudyApplicant::getUser, Function.identity()));
 
-              return new TeamDto(group, reports, formMap);
+              return new TeamDto(group, reports, applicantMap);
             })
         .toList();
   }
 
-  private boolean isFormRelevantToGroup(StudyApplicant form, StudyGroup group) {
-    return form.getStudyGroup().equals(group);
-  }
-
   public int deleteTeam(TeamIdDto dto, String email) {
     if (studyGroupRepository.existsById(dto.getGroupId())) {
       studyGroupRepository.deleteById(dto.getGroupId());
@@ -161,7 +156,7 @@ public void matchTeam() {
     matchCourseSecond(applicants, tag, current);
   }
 
-  public List<StudyGroup> matchFriendFirst(
+  public Set<StudyGroup> matchFriendFirst(
       List<StudyApplicant> applicants, AtomicInteger tag, AcademicTerm current) {
     // First matching
     // Make teams with friends
@@ -177,13 +172,12 @@ public List<StudyGroup> matchFriendFirst(
                       .orElseThrow(NoStudyApplicationFound::new);
               return StudyGroup.of(tag, current, partnerRequest.getSender(), receiver);
             })
-        .distinct()
-        .toList();
+        .collect(Collectors.toSet());
   }
 
-  public List<StudyGroup> matchCourseFirst(
+  public Set<StudyGroup> matchCourseFirst(
       List<StudyApplicant> applicants, AtomicInteger tag, AcademicTerm current) {
-    List<StudyGroup> results = new ArrayList<>();
+    Set<StudyGroup> results = new HashSet<>();
 
     List<PreferredCourse> preferredCourses =
         applicants.stream()
@@ -213,17 +207,17 @@ public List<StudyGroup> matchCourseFirst(
                           Collectors.mapping(PreferredCourse::getApplicant, Collectors.toList())));
 
           courseToUserMap.forEach(
-              (course, applicant) -> {
-                List<StudyGroup> matchedGroupList = createGroup(applicant, tag, current);
-                results.addAll(matchedGroupList);
+              (course, _applicants) -> {
+                Set<StudyGroup> matchedGroups = createGroup(_applicants, tag, current);
+                results.addAll(matchedGroups);
               });
         });
     return results;
   }
 
-  private List<StudyGroup> createGroup(
+  private Set<StudyGroup> createGroup(
       List<StudyApplicant> applicants, AtomicInteger tag, AcademicTerm current) {
-    List<StudyGroup> matchedGroupList = new ArrayList<>();
+    Set<StudyGroup> matchedGroups = new HashSet<>();
 
     while (applicants.size() >= 5) {
       // If the group has more than 5 elements, split the group
@@ -233,7 +227,7 @@ private List<StudyGroup> createGroup(
 
       // Create a group with only 5 elements
       StudyGroup studyGroup = StudyGroup.of(tag.getAndIncrement(), current, subGroup);
-      matchedGroupList.add(studyGroup);
+      matchedGroups.add(studyGroup);
 
       // Remove the elements that have already been added to the group
       applicants.removeAll(subGroup);
@@ -242,13 +236,14 @@ private List<StudyGroup> createGroup(
       // If the remaining elements are 3 ~ 4
       // Create a group with 3 ~ 4 elements
       StudyGroup studyGroup = StudyGroup.of(tag.getAndIncrement(), current, applicants);
-      matchedGroupList.add(studyGroup);
+      matchedGroups.add(studyGroup);
     }
-    return matchedGroupList;
+    return matchedGroups;
   }
 
-  private void matchCourseSecond(
+  private Set<StudyGroup> matchCourseSecond(
       List<StudyApplicant> applicants, AtomicInteger tag, AcademicTerm current) {
+    Set<StudyGroup> matchedGroups = new HashSet<>();
 
     Map<Course, PriorityQueue<StudyApplicant>> courseToUserByPriority =
         preparePriorityQueueOfUsers(applicants);
@@ -261,8 +256,10 @@ private void matchCourseSecond(
                   .filter(StudyApplicant::isNotMarkedAsGrouped)
                   .sorted(queue.comparator())
                   .collect(Collectors.toList());
-          createGroup(group, tag, current);
+          Set<StudyGroup> groups = createGroup(group, tag, current);
+          matchedGroups.addAll(groups);
         });
+    return matchedGroups;
   }
 
   private Map<Course, PriorityQueue<StudyApplicant>> preparePriorityQueueOfUsers(
diff --git a/src/main/java/edu/handong/csee/histudy/service/UserService.java b/src/main/java/edu/handong/csee/histudy/service/UserService.java
index a83c8fd..b6e1a65 100644
--- a/src/main/java/edu/handong/csee/histudy/service/UserService.java
+++ b/src/main/java/edu/handong/csee/histudy/service/UserService.java
@@ -206,11 +206,17 @@ public void editUser(UserDto.UserEdit form) {
         .ifPresentOrElse(
             tag -> {
               StudyApplicant applicant =
-                  applicantOr.orElse(StudyApplicant.of(currentTerm, user, List.of(), List.of()));
+                  applicantOr.orElseGet(
+                      () -> {
+                        StudyApplicant _applicant =
+                            StudyApplicant.of(currentTerm, user, List.of(), List.of());
+                        return studyApplicantRepository.save(_applicant);
+                      });
               studyGroupRepository
                   .findByTagAndAcademicTerm(tag, currentTerm)
-                  .orElse(StudyGroup.of(tag, currentTerm))
-                  .assignMembers(applicant);
+                  .ifPresentOrElse(
+                      group -> group.assignMembers(applicant),
+                      () -> StudyGroup.of(tag, currentTerm, List.of(applicant)));
             },
             () ->
                 applicantOr.ifPresent(