GroupShare CU5 (build 5111): Installation failed

Hi,

i have tried to upgrade from GS2017 CU2 (build 4993) to CU5 (build (5111). But the upgrade failed. It failed with message that it cannot find installation file ServerServices.msi in the "Package Cache" location on this server. The file is clearly unpacked there together with other SDL *.msi installers.

As consequence i cannot uninstall the "newest" (5111) corrupted version either. So the server basically needs to be wiped and reinstall everything from scratch. 

Did you anyone come across similar thing? Any hint would be very appreciated.

regards,

Fana