When you start a classic report from RTC (a report with no layout defined), it starts the report engine from the classic client. It can happen that after updating RTC, you end up with a version of RTC which is not compatible with the default classic client. In this case you will typically get this error message when trying to run the report:
Microsoft Dynamics NAV Classic client was opened from an untrustworthy component. Contact your system administrator.
Or if you have a test machine with multiple versions of RTC and classic you may want to start the classic client from another folder.
RTC finds the location of Finsql.exe in this place in registry:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\
So if you have any of the issues above, make sure that the classic client in this folder matches the version of RTC.
Lars Lohndorf-Larsen
Microsoft Dynamics UK
Microsoft Customer Service and Support (CSS) EMEA