TaxWorks (Tax Works) is a professional tax preparation program. There is an error in its update program that can possibly disable the RBackup Endpoint software by improperly overwriting a DLL file common to both programs with an older version, effectively reverting it improperly.
TaxWorks is usually updated very often, and this problem can show up with every update.
Best Practices for writing installers and updaters is to have them not revert shared DLLs to older versions, rather, to overwrite them only with newer versions.
Reinstalling or upgrading the RBackup Endpoint software solves the problem, and doesn't seem to adversly effect TaxWorks.
This is a problem with the TaxWorks upgrade software, and not with RBackup.
To solve this problem forever, the TaxWorks people are going to have to fix their intaller.