diff --git a/CHANGELOG.md b/CHANGELOG.md
index ec1b5eeb..a91f5630 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@
 * Fix: logging ignores not retrievable get_native_id if not supported by OS
 * Fix: report with enabled expand honors now provided filter proper
 * Improve: add options [logging] trace_on_debug and trace_filter for supporting trace logging
+* Fix: catch case where getpwuid is not returning a username
 
 ## 3.5.4
 * Improve: item filter enhanced for 3rd level supporting VALARM and honoring TRIGGER (offset or absolute)
diff --git a/radicale/utils.py b/radicale/utils.py
index b5b42694..1b5a016c 100644
--- a/radicale/utils.py
+++ b/radicale/utils.py
@@ -225,7 +225,12 @@ def user_groups_as_string():
     if sys.platform != "win32":
         euid = os.geteuid()
         egid = os.getegid()
-        username = pwd.getpwuid(euid)[0]
+        try:
+            username = pwd.getpwuid(euid)[0]
+        except Exception:
+            # name of user not found
+            s = "user=(%d) group=(%d)" % (euid, egid)
+            return s
         gids = os.getgrouplist(username, egid)
         groups = []
         for gid in gids: