diff --git a/src/changelog.lisp b/src/changelog.lisp
index 761a04c..ed12420 100644
--- a/src/changelog.lisp
+++ b/src/changelog.lisp
@@ -12,6 +12,8 @@
                               "ERROR-ON-WARNINGS"
                               "DYNAMIC-BINDINGS")
                :external-docs ("https://40ants.com/doc/"))
+  (0.11.1 2024-03-11
+          "* Fixed initite loop when the system is unknown to ASDF yet.")
   (0.11.0 2023-06-05
           "* Now docs builder tries to load system using either Quicklisp client or ASDF if system is not already loaded.
            * Also a bug was fixed - previously DOCS-BUILDER:BUILD function hanged in recursion in case if asdf system wasn't found.
diff --git a/src/utils.lisp b/src/utils.lisp
index 609a8b7..a28c269 100644
--- a/src/utils.lisp
+++ b/src/utils.lisp
@@ -50,7 +50,11 @@
     (labels ((recurse (system)
                (typecase system
                  ((or string symbol)
-                  (recurse (asdf:registered-system system)))
+                  (let ((found-system (asdf:registered-system system)))
+                    (unless found-system
+                      (error "Unable to find system \"~A\". Try to load it using ASDF or Quicklisp."
+                             system))
+                    (recurse found-system)))
                  
                  (asdf:system
                   (loop for item in (asdf:system-depends-on system)
@@ -60,14 +64,14 @@
                         when (and real-item
                                   (not seen)
                                   (asdf/system:primary-system-p real-item))
-                        do (pushnew real-item results
-                                    :test #'string=)
+                          do (pushnew real-item results
+                                      :test #'string=)
                         when (and real-item
                                   (not seen)
                                   (or all
                                       (not (asdf/system:primary-system-p real-item))))
-                        do (push real-item visited)
-                           (recurse real-item))))))
+                          do (push real-item visited)
+                             (recurse real-item))))))
       (recurse system)
       (values (sort results
                     #'string<)))))