Exporting the project using FCAdminTools fails with the error "A sharing violation occurred while accessing C:\Users\%username%\AppData\Local\Temp ... \lock.trs".
The lock.trs file is used by another process.
If it's ok to remove the old versions of document definitions and related files from the project, use the CompactProject command in FCAdminTools and try exporting the project again.
CompactProject /Project="https://FCSRV/1/SingleEntryPoint" /U=user /P=password
You can also compact the project using the user interface of the Project Setup Station:
navigate to the menu bar option Project > Compact.