Error when synching

[PaulNocero]

Checklist:-

• Upgrade to the latest release (alpha if available)
• Reproduce the issue
• Complete the information below
• Provide your OGcalsync.log file (attached)

OGCS Version: v2.11.6.0
Edition: Installed
Sync Direction: O->G

Bug Description
During sync, I very often get the pop-up error that is in the attached file. The sync appears to complete, but certain items don't always sync.

Steps to Reproduce the Issue

1. Go to...
2. Click on...

Any other information
Any additional information that may help troubleshoot the issue.
📎 Attach your OGcalsync.log file.

OGcalsync.log

[phw198]

The log lines of note are:-

2025-09-19 16:51:44,578 DEBUG 1  OutlookGoogleCalendarSync.Outlook.OutlookNew [67] -  Get the folders configured in Outlook
2025-09-19 16:51:44,589 DEBUG 1  OutlookGoogleCalendarSync.Outlook.OutlookNew [455] -  Finding default Mailbox calendar folders
2025-09-19 16:51:45,165 INFO  1  OutlookGoogleCalendarSync.Updater [304] -  Already running the latest version of OGCS.
2025-09-19 16:51:46,261 WARN  1  OutlookGoogleCalendarSync.Exception [519] -  Failed to recurse MAPI folders.
2025-09-19 16:51:46,262 WARN  1  OutlookGoogleCalendarSync.Outlook.Errors [33] -  [0x80040154] >> Class not registered (Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG))
2025-09-19 16:51:46,264 ERROR 1  OutlookGoogleCalendarSync.Exception [29] -  System.Runtime.InteropServices.COMException: Class not registered (Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG))
2025-09-19 16:51:46,289 ERROR 1  OutlookGoogleCalendarSync.Exception [22] -  Code: 0x80040154,-2147221164; Location: ThrowExceptionForHRInternal() in findCalendars() at offset 411 in OutlookNew.cs:495:40
2025-09-19 16:51:46,291 DEBUG 1  OutlookGoogleCalendarSync.Extensions.MessageBox [75] -  Calendar Folders: A problem was encountered when searching for Outlook calendar folders.
Class not registered (Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG))
2025-09-19 16:51:48,715 DEBUG 1  OutlookGoogleCalendarSync.Outlook.OutlookNew [413] -  Default Calendar folder: Calendar
2025-09-19 16:51:48,721 DEBUG 1  OutlookGoogleCalendarSync.Outlook.OutlookNew [414] -  Folder type: olNotExchange
2025-09-19 16:51:48,743 INFO  1  OutlookGoogleCalendarSync.Outlook.ExplorerWatcher [20] -  Setting up Explorer event watchers.
2025-09-19 16:51:48,746 DEBUG 1  OutlookGoogleCalendarSync.Outlook.ExplorerWatcher [21] -  Watcher needed for 0 existing explorers.
2025-09-19 16:51:48,903 WARN  1  OutlookGoogleCalendarSync.Exception [19] -  Failed to get EntryID for folder: iCloud
2025-09-19 16:51:48,904 FAIL  1  OutlookGoogleCalendarSync.Exception [22] -  System.Runtime.InteropServices.COMException: An unexpected error has occurred.
MAPI was unable to load the information service C:\ProgramData\Apple Inc\iCloud\Outlook\APLZOD64.dll. Be sure the service is correctly installed and configured.
2025-09-19 16:51:48,904 FAIL  1  OutlookGoogleCalendarSync.Exception [22] -  Code: 0x8837007E,-2009661314; Location: get_EntryID() in UpdateGUIsettings_Profile() at offset 989 in MainForm.cs:324:33

Ultimately the error on a particular folder is 0x80040154 which is covered in the wiki - unfortunately, the only known fix is an uninstall and reinstall of Outlook.

However, I see there is a later error too for "Failed to get EntryID for folder: iCloud" and An unexpected error has occurred. MAPI was unable to load the information service C:\ProgramData\Apple Inc\iCloud\Outlook\APLZOD64.dll. Be sure the service is correctly installed and configured.. I wonder if it's the same folder that is causing both problems? Could you remove it (temporarily at least) and see if that helps?