diff --git a/dali/daliadmin/daadmin.cpp b/dali/daliadmin/daadmin.cpp
index e44576f539b..e456c541c58 100644
--- a/dali/daliadmin/daadmin.cpp
+++ b/dali/daliadmin/daadmin.cpp
@@ -2273,8 +2273,8 @@ void checkFileSizeOne(IUserDescriptor *user, const char *lfn, bool fix)
         Owned<IDistributedFile> dFile = queryDistributedFileDirectory().lookup(dlfn, user, AccessMode::tbdRead, false, false, nullptr, defaultPrivilegedUser, 30000); // 30 sec timeout
         if (dFile)
         {
-            bool locked = false;
-            COnScopeExit ensureUnlock([&]() { if (locked) dFile->unlockProperties(); });
+            bool fileLocked = false;
+            COnScopeExit ensureFileUnlock([&]() { if (fileLocked) dFile->unlockProperties(); });
             if (dFile->querySuperFile())
                 WARNLOG("Skipping: file '%s' is a superfile", lfn);
             else
@@ -2288,10 +2288,19 @@ void checkFileSizeOne(IUserDescriptor *user, const char *lfn, bool fix)
                     {
                         if (fix)
                         {
+                            COnScopeExit ensurePartUnlock([&]() { part.unlockProperties(); });
                             offset_t partSize;
                             try
                             {
                                 partSize = part.getFileSize(true, true);
+                                if (!fileLocked)
+                                {
+                                    // we lock the file once, so that the individual part lock/unlocks are effectively a NOP
+                                    dFile->lockProperties(30000);
+                                    fileLocked = true;
+                                    PROGLOG("File '%s' has missing @size attributes", lfn);
+                                }
+                                part.lockProperties(30000);
                             }
                             catch (IException *e)
                             {
@@ -2299,12 +2308,6 @@ void checkFileSizeOne(IUserDescriptor *user, const char *lfn, bool fix)
                                 e->Release();
                                 continue;
                             }
-                            if (!locked)
-                            {
-                                part.lockProperties(30000);
-                                locked = true;
-                                PROGLOG("File '%s' has missing @size attributes", lfn);
-                            }
                             PROGLOG("Part %u: Setting @size to %" I64F "u", p+1, partSize);
                             attrs.setPropInt64("@size", partSize);
                         }