Power Platform Community Forum Thread Details

We recently had some sort of Exchange EXO migration (unsure of what that is, I am a bit new to these things). I had a Power Query that imported data from Mail Exchange flawlessly, no problem. Now it says: DataSource.Error: ErrorNonExistentMailbox: No mailbox with such guid. Details: DataSourceKind=Exchange ...

I cleared permissions & cache. The preview navigator shows same error. AI seems pretty clueless on what's going on. I suspect this is exchange migration that happened recently. But HELP! I used VBA to get around this problem but it is nowhere close to as efficient & fast.

Categories:

Error handling

Hi,

That error is commonly seen after an Exchange mailbox migration or mailbox recreation. Power Query's Exchange connector may still be referencing the old mailbox GUID, which no longer exists, even though the email address remains the same.
A few things to check:

Open the Power Query source step and verify it's using the current mailbox address rather than a cached mailbox identifier.
Remove and recreate the Exchange data source connection instead of only clearing permissions.
If you're connecting to a shared mailbox, confirm the mailbox still exists and wasn't recreated during the migration.
Ask your Exchange/O365 administrator whether the mailbox was migrated, restored, or recreated recently, as any of those can result in a new mailbox GUID.

Since the Navigator is failing before data is returned, this points more to a mailbox identity issue than a Power Query issue. If the migration was recent, your Exchange admin should be able to confirm whether the mailbox GUID changed and whether the connection needs to be rebuilt.

Thanks & Regards,

Manoj Annavajjala