This is caused by Windows incorrectly caching AMP libraries when it shouldn't. Resolution is as follows:
- Shut down AMP entirely. Use
ampinstmgr stopallin a command prompt and then use Task Manager to kill any remaining
- Run the original AMP installer (AMPSetup.msi) in repair mode.
ampinstmgr --nocache upgradeallin a command prompt.
- Reboot the system - do not skip this step!