Stuff…

A clients disk filled up and Plesk was starting but going to the login page prompted:

Fatal error: Call to undefined function of_get_key_by_product() in C:\Program Files\Parallels\Plesk\admin\plib\common_func.php3 on line 4501

Going to “C:\Program Files\Parallels\Plesk\admin\repository” the registry.xml file was 0 bytes in size.  Renamed this to registry.xml.old and restarted Plesk.

Plesk came up and the login page worked fine without the error.

Parallels forum post gave a hint:

• http://forum.parallels.com/printthread.php?t=97999