Processing archive mailbox XXXX completed with warning: Mailbox XXXX is already processed by another job

[MaartenA]

Hi,

For a few weeks now I have been seeing the message Processing archive mailbox XXXX completed with warning: Mailbox XXXX is already processed by another job in various Exchange jobs. I only see this warning with archive mailboxes while no overlapping jobs are running. Are others also seeing an increase regarding this warning?

Case # 07430043

[Mildur]

Hello Maarten

I found a few similar cases, but nothing widespread at the moment.
In one of the cases, the same archive mailbox GUID was found by multiple mailboxes, which is strange. Our support team is still investigating the situation.
For now, please continue to troubleshoot the issue with our support engineer.

Best,
Fabian

[bielekovve]

Hi,

I just stumbled over that warning in my jobs, too... We have eight exchange-jobs which show this warning... Should I better open a case now?

9/25/2024 8:29:28 PM :: Processing archive mailbox XXX completed with warning: Mailbox XXX is already processed by another job
etc.

Kind regards...

[Mildur]

Yes please. The error doesn't have to have the same cause for every case.

Best,
Fabian

[bielekovve]

ok... I will soon open a case... the warnings in the affected jobs began on the evening of September 9th. I also see the following errors which were absolutely new:

9/10/2024 2:32:48 AM :: Processing archive mailbox XXX failed with error: Mailbox is not fully configured.
9/10/2024 2:34:08 AM :: Processing archive mailbox XXX failed with error: Object reference not set to an instance of an object. :: 0:01:14
9/10/2024 2:35:22 AM :: Processing archive mailbox XXX completed with warning: Mailbox XXX is already processed by another job

[bielekovve]

Case #07439213 — several warnings/errors when backing up Exchange mailboxes (I am just uploading the logs)

[Mildur]

Hi all

Our QA team is currently investigating this issue.

Best,
Fabian

[edh]

+1 We found this issue, but it get resolved with the retrys...

[mrjensen5147]

+1

Whenever archive is disabled, the error message comes in the first backup. But retry is attempting objects where archive is enabled.
In retrys it fails again...

[bielekovve]

We also see errors (the job status says "Warning"):

Case #07441237 — Mailbox not fully configured

10/8/2024 2:42:13 AM :: Processing archive mailbox xyz@abc.de failed with error: Mailbox is not fully configured.
I think we will wait for the fix and that error will disappear, too...

In our case all the warnings/errors occured on 9th/10th of September for the first time... Is there anything known about a change done by Microsoft?

Kind regards...

[Mildur]

Hi bielekovve

Our QA team is currently investigating the issue discussed in this topic.
We will update the topic when we have news about a potential fix or workaround.

Best,
Fabian

PS: We released a new patch for other top issues of V8: https://www.veeam.com/kb4656

[mjr.epicfail]

Hi Fabian,

Was there ever a fix for this.
Im now seeing warnings aboute this too: (Archive) Mailbox is not fully configured

[Mildur]

Hi Danny,

All cases in this topic were for version 7 and were closed without a fix.
In one case, backups started working again; in another, the customer waited for v8.1 and upgraded.

Could you please open a case and provide me with the case number?

Best,
Fabian

[mjr.epicfail]

Hi Fabian,

In my case the catchall configuration was the problem, when configured as backup items -> tenant. The issue went away.
There was no archive mailbox on the user(s), however somehow Veeam thought so.

I guess the enumeration of objects differs from the the 2 ways to backup a tenant.

[Mr.Austria]

Same here starting last week, two days after update to Version 8.1.2.180, after one successfully backup without problems.
Now seeing this warning too: (Archive) "Mailbox is not fully configured" for only one mailbox.
Also the specific mailbox don't has configured an archive mailbox at all.
Disable the catch all function is not a good option for us.

[MaartenA]

I've been having the same problem in several tenants for the past few days. It's a different message than the one described in this post. So, indeed, the message (Archive) "Mailbox is not fully configured"

[pat_ren]

I've also started seeing this error popping up for random users/random clients (across 8500 users) across multiple servers - just a handful of users in specific jobs all randomly experiencing this error.
Never had it before until recently.

Will arrange to log a Veeam case - but putting this here for others to see too, doesn't seem to be an issue on our end based on what i'm seeing.

[pat_ren]

Unfortunately can't edit my post above - I know this is an old thread, but seems to be the most current discussion on this issue.
Have uploaded logs from 2 servers, provided examples of 4 different clients with the issue (there are many more)
Case #07859839

[Polina]

Hi All,

We're already working in this issue and opened a case with Microsoft. Please stay in touch with our support engineers - this will help us to troubleshoot and resolve the issue faster. Thanks!

[admd]

Hi Danny,

All cases in this topic were for version 7 and were closed without a fix.
In one case, backups started working again; in another, the customer waited for v8.1 and upgraded.

Could you please open a case and provide me with the case number?

Best,
Fabian

Hello Fabian,

Sorry to hijack this topic.
Case #07828325 opened since mid september and nothing changed.

For the error : Processing archive mailbox XXX failed with error: Mailbox is not fully configured.

Thanks a lot !

[raftbone]

The error message "Mailbox is not fully configured" started on our infrastructure today as well.

[Pronoxis]

Joining the fray with the error message "Mailbox is not fully configured", which started in our daily Archive jobs on 16-OCT-2025, but on Veeam Data Cloud Microsoft 365.

[Pete@DPY]

I'll jump in here also, we have also noticed this across multiple tenants since going to 8.1.2, increasing each day. Error - Processing archive mailbox XXX failed with error: Mailbox is not fully configured

[mjr.epicfail]

I don't think this is related to a specific vb365 build.
As Polina already mentioned before, everyone who encounters this issue should create a supportcase.
This will help Veeam help Microsoft identify and solve the issue.

[Polina]

The rootcause has been identified and is now in fixing. If your environment is impacted, please stay in touch with our support team to get the fix once its ready.

Thanks!

[raftbone]

Will this fix be released anyway soon in a next version? Or do we HAVE to create a support case to get this fix?

[jasonede]

We've had this too but was just sporadic and re-running the job always cleared it up. Now it's happening on a handful of mailboxes and re-running does not resolve it.

[Polina]

@raftbone

You'll get faster assistance via support.

[raftbone]

Any internal ID from Veeam or a Build number where I can reference to when opening a case?

[Polina]

It's not needed; just describe the issue you're seeing.