Plesk Control Panel fails to load. The following error is displayed:
Warning: file(/etc/psa/psa.conf) [function.file]: failed to open stream: No such file or directory in C:\Program Files\SWsoft\Plesk\admin\plib\class.Conf.php3 on line 33
Unable to read Control Panel configuration file
In general the reason of Open stream error is lack of permissions on some plesk binary or library files. Commonly it appears because of incorrect hotfix installation , when some files are replaced manually. Also some files could be replaced with some third party application.Some particular case (which appears more often) could be the following:
Plesk could not execute the method of detecting Plesk configuration. It could be caused by insufficient permissions on file C:\WINDOWS\system32\libmysql.dll due to the reasons above.
For this particular case it is necessary to inherit permissions from C:\WINDOWS\system32 folder and make sure that psaadm and psacln accounts have the following permissions on this file: Read, Read&Execute and List Folder Content.
Note: This case is provided like an example. In fact the file with missed permissions could be the different. For other cases try to use Process Monitor(Filemon option) utility to track filesystem and find such files.