Hello!
In the end (Running assembly installer for /bin/episerver.dll) of the upgrade process using EPiServerInstaller.exe I get the following error message:
The installation failed, and the rollback has been performed. [The configuration registry key is invalid]
// Stefan
Hi,
I recently had the same problem upgrading a 4.50 installation to 4.51.
I managed to solve it (after some help) by removing the HKLM/System/CurrentControlSet/Services/EPiServer4/Performance collection of keys.
This seemed to allow me to upgrade. Obviously before removing these keys from the registry, make a backup of them in case the same fix does not apply.
Rich M