Outlook troubleshooting

Known issues

Events created in Outlook are not synchronized to the server

Affects Outlook 64Bit >= 2404 Build 16.0.17531.20140
Does not affect Outlook 32 Bit.

Symptoms

Events created in Outlook do not appear on the server.

Outlook error message in outlook logs:

<Error>
  <Hr>80020012</Hr>
  <Message>Arithmetic overflow.</Message>
  <File>src\outlook\pstprx\storeas\eascontentuploader.cpp</File>
  <Line>182</Line>
</Error>

Resolution

Downgrade to Outlook < 2404, or switch to Outlook 32 Bit.

Removing and then readding the primary Calendar breaks synchronization

Affects all known versions.

If a FolderSync response reports the addition of the default Calendar folder then this breaks synchronization completely because Outlook fails to process the response.
We can get into this situation after removing/unsubscribing the primary calendar.

Symptoms

New Folders created on the server don’t appear on the client after triggering a resync.

Outlook error message in outlook logs on processing a FolderSync response.

<Error>
  <Hr>8004010f</Hr>
  <Message></Message>
  <File>src\outlook\pstprx\storeas\eashierarchydownloader.cpp</File>
  <Line>120</Line>
</Error>

Resolution

Reset the account (see below).

Removing and readding Contacts folders doesn’t result in them showing up in Outlook

After removing all Contacts folders and readding them, a restart of outlook is required to get them to show up again.

Symptoms

There are no contacts visible in Outlook.

Resolution

Restart outlook.

Unrecoverable sync error

Outlook can hit unrecoverable sync errors, but it’s unclear how to trigger this issue.

Symptoms

Outlook error message:

<Error>
  <Hr>80004005</Hr>
  <Message>Unrecoverable sync error, cannot sync, manually delete OST.</Message>
  <File>src\outlook\pstprx\storeas\eashierarchydownloader.cpp</File>
  <Line>78</Line>
</Error>

Resolution

Reset the account (see below).

Sync loops

Certain circumstances can result in endless synchronization loops. Sync loops are most visible on the server as there will be a continuous stream of requests from the same device.

Example scenarios:

  • With the calendar unsubscribed: Outlook pings the calendar folder, which triggers a FolderSync, which doesn’t report the calendar folder, which results in a ping that includes the calendar folder …..
  • A client pings for an unknown collection -> this triggers a sync with an unknown collection
  • Ping Status 7 because of disabled calendar folders being included in request, leads to folder sync response that adds Contacts folder and sync request. Starts over with Ping.

A device stuck in a sync loop will appear operational (there’s no UI feedback), but will not synchronize anything.

Reset procedure

If a device is stuck in a bad state it can be impossible to do get it out of this state, and it’s hard to diagnose what’s not working (you may end up with partial functionality).

Potential issues:

  • Certain folders are not included in Ping and/or Sync requests, which means they no longer update.
  • FolderSync keeps failing and therefore new folders never make it to outlook.
  • Ongoing sync-loop preventing any sort of useful synchronization work.

There is one reliable reset strategy:

  • Stop Outlook
  • Delete the .ost file for the account in C:\Users\$USERNAME\AppData\Local\Microsoft\Outlook
  • Delete the device in the roundcube activesync settings
  • Start Outlook again, which will resync from scratch.

Do not just remove the server-side state via roundcube. While this may sometimes work, it’s unreliable and can also leave you with random folders not working, leaving you in a hard to diagnose situation.

Capturing outlook debug logs

First check “Enable troubleshooting logging”.

image.png (577×705 px, 108 KB)

Restart Outlook after this step.

Activesync logs should now be collected in a location like this:

image.png (648×1 px, 256 KB)
image.png (648×1 px, 220 KB)