When you use the MSTFS data-synchronization DLL and put it in the SpiraTeam BIN folder it will case the error to appear:

Could not load file or assembly 'Microsoft.TeamFoundation.WorkItemTracking.Client.Cache' or one of its dependencies. An attempt was made to load a program with an incorrect format.

What you need to do therefore is just open up the IIS Management Console, locate the SpiraTeam Application Pool (called SpiraTeam AppPool) and switch it to run as a 32-bit application.

You may then get the following error message:

Could not load file or assembly 'MsTfsDataSync' or one of its dependencies. An attempt was made to load a program with an incorrect format.

This message is displayed because the DataSyncService.exe is also running in 64-bit mode. To fix the issue, download the replacement DataSyncService.exe file from the Attachments tab of this ticket. This has been recompiled to work in x86 mode. We have the following versions attached to this ticket:

In addition, for those customers using the DesktopDataSync with our hosted service, we have updated the main Desktop Data Sync installation package to install both the 32-bit and 64-bit versions in separate folders. So you no longer need to get a different version from this article. Instead in the Windows Start Menu, choose the DesktopDataSync (32-bit) to use with TFS.