We might come across the below error in the PST import/export

Error code: -2146233088

Unable to open PST file ‘\\fileshare\Archive\testuser.pst’. Error details: Header file length is zero. If this file is from a previously failed pst export, please delete the file and resume the export. –> Header file length is zero. If this file is from a previously failed pst export, please delete the file and resume the export.

There can be so many issues causing this factor and below tips can be helpful:

1) The mailbox import/export uses the Microsoft Exchange Mailbox Replication service on the CAS server. When a  import/export request is triggered a remote powershell connections will be established from the source CAS to the appropriate destinations to the shared folder to initiate this process. So better to have the shared location network drive in the same VLAN where the exchange is hosted and this will speed up the import/export option.

2) Restart Microsoft Exchange Mailbox Replication service – Since the MRS service is handling this job and if the MRS is stuck processing the huge jobs a restart of this service will definitely help  to speed up the migration process.

3) Remove the Failed import/export requests with the below commands

Get-MailboxExportRequest -Status Failed | Remove-MailboxExportRequest

Get-MailboximportRequest -Status Failed | Remove-MailboximportRequest

4)  We can run this command import/export to exclude and skip few errors

For Import –
New-MailboxImportRequest  -Mailbox  -filepath ‘\\fileshare\Archive\testuser.pst’ -Baditemlimit unlimited -AcceptLargeDataLoss -Priority High -AssociatedMessagesCopyOption Copy  -Confirm:$false  -ConflictResolutionOption KeepLatestItem  -ExcludeDumpster
For Export-
New-MailboxExportRequest  -Mailbox  -filepath ‘\\fileshare\Archive\testuser.pst’ -Baditemlimit unlimited -AcceptLargeDataLoss -Priority High -AssociatedMessagesCopyOption Copy  -Confirm:$false  -ConflictResolutionOption KeepLatestItem  -ExcludeDumpster

5) Also better to check the free space available on the shared network drives where the PST export is happening.  Also better to see the free space available on the disk where the database resides from where the PST export/import is happening.

6) If we are experiencing a mailbox import/export for a specific user a mailbox repair might also help. We can perform the mailboxrepair with the below command.

New-MailboxrepairRequest –Mailbox “usernanme” –CorruptionType ProvisionedFolder,SearchFolder,AggregateCounts,FolderView