Cause
Launcher.old.exe is missing from ...\MAS90\Launcher\ folder
.NET Issues
Resolution
Restore ...\MAS90\Launcher\Launcher.old.exe from backup
If issue is happening to a specific workstation, run repair on .NET
Open Control Panel, Programs and Features
Locate the Framework 4 entry Right click and select Repair
Locate the Framework 4.5 entry and perform the same steps.
Locate the Framework 4.5 SDK entry (if installed) and perform the same steps
https://support.na.sage.com/selfservice/viewdocument.do?noCount=true&externalId=79095&sliceId=1&isLoadPublishedVer=&docType=kc&docTypeID=DT_Article&stateId=10907&cmd=displayKC&dialogID=458590&ViewedDocsListHelper=com.kanisa.apps.common.BaseViewedDocsListHelperImpl&openedFromSearchResults=true