When attempting to import a package, or an individual SDLXLIFF file that you have been working on, you get the following error message:
 

FPS_ERROR: File processing error. BCM Document Paragraph mismatch

 

Workaround: Use Perfectmatch

Create a new export package, or download the individual SDLXLIFF file. Once you have it open in Studio, apply PerfectMatch, using the SDLXLIFF you were unable to upload (or the SDLXLIFF from the package you were unable to upload). When finished, create a return package (if you are using packages) or upload the new SDLXLIFF file.
 

Solution

The solution is to follow the standard process for working with packages in Trados Accelerate / Cloud / Enterprise / Team. Be aware that third party tools can also affect the unique paragraph unit IDs contained within SDLXLIFF files.

When Language Cloud imports an individual SDLXLIFF file, or a package containing an SDLXLIFF file, it checks that it is the correct file by matching the SDLXLIFF's paragraph unit IDs against the ones from the previous version. If the file has been modified in such a way that these paragraph unit IDs no longer match, the file is unable to be imported.

One way in which the file(s) can be modified is when using third party software. For example, in one case memoQ was used as the offline translation tool, and mq metadata was inserted throughout the whole SDLXLIFF file. It was therefore not recognised by Trados Enteprise as part of the return package.