Steps to reproduce
1. Install SiteEditor 1.1-Win to Plesk 11.0.9.
2. Machine has SMB 10.2 (Win) with two sites created in SiteEditor.
3. Via PMM, migrate domains from SMB 10 to Plesk 11. The migration finishes without errors.
4. Open the migrated domain > Hosting Panel > Websites& Domains. Find the icon to open the site in SiteEditor and click on it.
As result, you receive the 500 Internal Server Error. SiteEditor does not open.
ResolutionIn order to fix this issue, you need to launch the following command line:
c:\windows\system32\inetsrv\appcmd.exe set apppool /apppool.name:SiteeditorWebAppPool /enable32BitAppOnWin64:true