Stalled Due to Target Processor in Exchange Server Migrations

Ideally, unknown errors shouldn’t halt Exchange move requests whether the destination is another on-premise server or the M365 cloud. However, sometimes during migration, the Exchange Server shows a “stalled due to target processor” error.

If not fixed on time the entire operation is in jeopardy. Don’t worry with this write we will teach you how to confirm, figure out the underlying cause, fix, and even bypass the issue entirely.

Confirming a Stalled Due to Target Processor Error

There are many different kinds of errors that can happen during a migration scenario all with drastically different fixing steps. So figuring out the correct error becomes all the more important. This has the added benefit of preventing the admin from wasting time on solving false positive issues.

As there is an upcoming release of Exchange Server 2025 later this year many organizations will be looking to transition into it so admins must be ready for all sorts of errors they may encounter and take preventative steps to ensure a smooth transition.

You can see by monitoring the current move request by typing the following in an existing or new Exchange Management Shell instance.

Get-MoveRequest -Identity <User> | Get-MoveRequestStatistics -IncludeReport | FL

The regular PowerShell window can also be used but you must first establish a connection between it and the Exchange Server.

This cmdlet works regardless of how the move request was initiated (whether through the Exchange Admin Center (EAC) or via PowerShell).

If after running this command you see an error message like the one below:

{DataExportTransientException: MapiFxProxyTransientException: The data export was cancelled

due to a timeout. The destination didn't respond in time. --> The data export was cancelled

due to a timeout. The destination didn't respond in time., DataExportTransientException:

MapiFxProxyTransientException: The data export was cancelled due to a timeout. The

destination didn't respond in time. --> The data export was cancelled due to a timeout. The

destination didn't respond in time., DataExportTransientException:

MapiFxProxyTransientException: The data export was cancelled due to a timeout.

Then it is a positive indication that your server has encountered a Stalled Due to Target Processor error

Once the confirmation part is done let’s learn the reasons behind this issue.

Why Admins See Stalled Due to Target Processor Error during Migrations?

Knowing what causes the error not only helps to fix it but also stops it from recurring in the future. With that being said here is what Microsoft lays out as the cause.

MRS Proxy inside any mailbox move request is improperly configured with the on-premises Exchange Server 2013 Client Access server (CAS).

Although in their official statement, they explicitly mention the 2013 edition the problem can occur in any of the later versions as well.

Apart from that it is found that neither the Exchange Admin Center (EAC) nor PowerShell-based migration method is directly linked to a higher occurrence of “StalledDueToTarget_Processor” errors.

Now we know why the error is there let us see how to fix it.

Step-by-Step Guide to Resume the Process after the Error

Start by stopping the MSExchangeMailboxReplication service. Open the Services module and scroll till you see the Microsoft Exchange Mailbox Replication option > Right-click and hit Stop.

Open File Explorer to find the MSExchangeMailboxReplication.exe.config file in your system:

The default path looks something like this

<Exchange Installation Path>\Program Files\Microsoft\Exchange Server\V15\Bin\MSExchangeMailboxReplication.exe.config

Once you successfully find the file Right click > Open with > Notepad. All you need to do is change the DataImportTimeout setting from whatever the default value is to 20.

Once done hit Save.

Go back to the Services page and restart the MSExchangeMailboxReplication service.

Repeat this for all CA servers, change the DataImportTimeout setting to 20.

Wait at least four hours for the migration batches to resume as usual.

If the error persists you can try to repair the exchange database as it is quite possibly in a corrupt state.

Use Alternative Solution to Bypass Stalled Due to Target Processor Error

The SysTools Exchange Migration tool provides the admin an option to bypass such errors that hamper the regular migration process. No longer does the admin have to rely on confusing PowerShell scripts or have to stay limited with the slow and archaic GUI of EAC.

This tool can very easily migrate the entire Exchange 2019 to the Office 365 cloud.

Just use the steps given below:

Step 1. Install the tool on your system Select Exchange Server as the Source and Microsoft 365 as the destination.

Step 2. Scroll to the workload area and select the items you need to move, options include email, contact, calendars, etc. You can also apply individual date filters to each workload if need be.

Step 3. In the Source Screen fill in the details and perform the validation.

Step 4. Likewise, Validate the Target as well.

Step 5. In the User mapping screen select any one option and press Next.

Step 6. Use the preview screen to view the user list, select the one whose data you want to move then apply priority, validate, and start migration.

Conclusion

Now the admins should no longer face the stalled due to the target processor error message during Exchange mailbox migrations. We gave the exact steps with visual aids to help admins fix the issue in minimal possible time.

Moreover, here admins were introduced to the best alternative for Exchange Server migration in both on-premise and cloud migration scenarios.