When migrating a batch of public folders from a local Exchange Server to Exchange Online (Microsoft 365), you might encounter a situation where not all the public folders are migrated to the cloud. When you look into the logs of migration, you might see one or more time-out errors. Below is a sample of one of the errors:
FailureType: “DataExportTransientException”
Message: “MapiFxProxyTransientException: MapiFxProxyTransientException: The data export was canceled due to a timeout. The destination didn’t respond in time…”
DataContext: “Folder: type Generic, wkf None, entryId [len=46, data=00000000696B95D9245A174B9BE940B86930B9BC01005B7769EBC1C00E438
E951DAC68D3FD86000035D08E1E0000], …”
You can encounter this error occurs when starting the batch migration from the Exchange Admin Center (EAC) from your local Exchange Server or using the Exchange Online PowerShell cmdlets while connected to the Exchange Online.
Now, let’s see the reasons behind this error and the solutions to resolve it.
Reasons for DataExportTransientException Error
There could be many reasons why this error occurs. Here are some common reasons when it comes to this particular failure type.
- Corrupted Public Folders: Corruption in public folders is one of the common reasons for this error. This means that some folders in the migration batch may be corrupted or being seen as corrupted, thus preventing you from executing a successful data export.
- Timeout Issues: If the migration is taking a very long time and there are connectivity or internet performance issues, then this might cause the destination server to cancel the data import.
- Misconfiguration of the Exchange Server: Misconfiguration of Exchange Server, specifically of the Microsoft Replication Service (MRS) proxy, might lead to such migration failures.
Possible Solutions to Fix DataExportTransientException Error
You can first check the configuration of Exchange Server to confirm that the Microsoft Replication Service (MRS) is running well and there are no misconfigurations. Then, check the bandwidth consumption and network load. If these two are cleared, you can re-run the migration batch to confirm if the problem has been resolved. If the problem still persists, you need to do the following.
Step 1 – Get Information of the Migration Batch
You can run the below command to export the migration request statistics from the migration batch to an XML file. For this, open the Exchange Management Shell (EMS) and run the following command:
Get-PublicFolderMailboxMigrationRequest -Status Failed | Get-PublicFolderMailboxMigrationRequestStatistics -IncludeReport -DiagnosticInfo "verbose,showtimeslots" | Export-Clixml migrationStats.xml
Step 2 – Find the Name of Public Folder
After the export is complete, you need to open the XML file and perform a search to find the public folder. To make it easier, you can execute the below command to automatically search the XML file and save the results in a text file.
$report=Import-Clixml migrationStats.xml
$report.report.failures | where {$.FailureType -eq 'DataExportTransientException'} | Select-Object -ExpandProperty DataContext > "text file path"
This will export the entry ID from the symptoms section of the XML file but this will not be readable and cannot match it with the name of public folder. To do so, you can run the below command.
Get-PublicFolder \ -Recurse | where {$_.EntryId -eq <public folder entry ID>}
Step 3 – Export the Data from Public Folder
The next step is to connect with an Outlook application and export public folder to PST file. For this,
- Open Outlook with a profile that has full access to the public folder.
- Click on File.
- Click on Open & Export.
- Click on Import/Export and select Export to a file.
- On the next screen, select the Outlook Data File (.pst) option and click Next.
- Select the public folder and then select the Include subfolders option.
- Select the location to save the PST file and finish to process.
Step 4 – Remove the Corrupted Public Folder
Since you’ve managed to export the public folder to PST, you can remove it from the setup. Use the command as given below.
Remove-PublicFolder -Identity <public folder entry ID>
After this is complete, you need to remove the public folder from the NON_IPM_SUBTREE. However, first verify that the public folder exists. For this, use the below command.
Get-PublicFolder -Recurse \NON_IPM_SUBTREE | ? name -like "<public folder name>"
If the public folder is present, you can run the below command to remove it from the NON_IPM_SUBTREE.
Get-PublicFolder -Recurse \NON_IPM_SUBTREE | ? name -like "<public folder name>" | Remove-PublicFolder
Step 5 – Re-run the Migration Batch
After the above has been completed, you can re-run the command to resume the migration batch and wait till the status of migration batch is displayed as synced. Then, complete the migration batch.
An Alternative Solution to Migrate Public Folders to Microsoft 365
When using the native methods to migrate public folders, you may encounter various issues or errors, including the DataExportTransientException error. To prevent such issues and migrate the public folders and other items from on-premises Exchange Server to Microsoft 365, you can take the help of a specialized Exchange migration tool.
Stellar Migrator for Exchange is one such reliable Exchange migration tool that simplifies the process of migrating public folders and other data from on-premises Exchange Server to Microsoft 365. This tool has an intuitive, GUI-based interface that reduces the complexity of the process. It ensures seamless and error-free migration even when dealing with large or corrupted public folders. The tool ensures complete data integrity and minimal downtime during the migration process. It can also facilitate migration of public folders, user mailboxes, archives, and other data between on-premises Exchange Servers and also between Microsoft 365 tenants.
Conclusion
Migrating public folders is not a straight forward operation. You need the expertise and resources to migrate the folders. You may also encounter various errors, such as the DataExportTransientException error. Above, we have discussed how to resolve this error.
When migrating data, it’s important to have a smooth operation with minimal impact or delays. To ensure this, you can use Stellar Migrator for Exchange – a specialized Exchange migration tool that reduces the effort and complexity when it comes to migration from local Exchange Server to Microsoft 365 and vice-versa.
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