Parallels Plesk 11.5 to 12 Upgrade Problems

Parallels Plesk 11.5 to 12 Upgrade Problems

After recently upgrading a Windows 2008 R2 web server from Parallels 11.5 to Parallels 12, I ran in to a series of fairly serious issues that I thought I would document here in the hopes that it might help others.  These were previously listed on my Parallels Plesk 12 Review as I effectively had to stop the review due to the problems but now all is working again, I thought it better to separate the two. What is interesting to note about my upgrade from Plesk 11.5 to 12 is that I received no warning messages or errors during the whole upgrade process (I sat and watched the whole thing having had issues with the upgrades from Plesk 10 to 11 in the past).  I had restarted the server both before and after the update to ensure as many resources as possible were available during the installation and the new version was properly ‘bedded in’ when I started using it. Once the upgrade was complete I browsed straight to a couple of customer websites and saw they were running fine and sent a few test emails and they were correctly routed – great I thought!

Here There Be Errors…

Having been lulled in to a false sense of security by my brief tests and lack of error messages, I was dismayed to find the Plesk Panel effectively broken and on further investigation, half of the websites offline.

Plesk Panel Problems

All Subscriptions Missing

Right off the bat, clicking ‘Hosting Services > Subscriptions’  shows ‘No Items Found’ – initiate panic.


  1. The root cause was a Plesk database inconsistency.  An incorrect column had been created ‘externalid’ (duplicating the ‘external_id’ values) in ‘domains’ table.
  2. In order to fix the issue first, create a backup of psa database.
  3. Restore the pre-upgrade dump of psa databases.
  4. Remove the ‘externalid’ field from domains table in the psa database.
  5. Run the Plesk database upgrade process manually:
    C:\Program Files (x86)\Parallels\Plesk\admin\bin>dbupgrade –upgrade –from-version=11.5.30 –to-version=12.0.18

Can’t Login to Subscriptions

I was able to view my subscriptions via the ‘Business Operations > Subscriptions’ section of Plesk but clicking login yields an error like “Error: Subscription with such external id B7D16FCB-F669-4BA5-ABBA-987E3ADED085 does not exist

Solution: The steps above for fixing the missing subscriptions also solved this issue,

Can’t Login as Reseller

A new feature I was pleased to see was the ‘Login’ feature under Hosting Services > Resellers  but unfortunately clicking it simply returns me to the homepage of the Plesk with an error like “login_up__billing_local_credentials_for_global_account

Solution: The steps above for fixing the missing subscriptions also solved this issue,

Plesk Panel HTTP 500 Internal Server Error

Plesk Control Panel PHP ErrorsAfter all the other issues were sorted, I started receiving intermittent PHP errors on page loads of the Plesk Panel with the following error reported:

HTTP Error 500.0 – Internal Server Error

C:\Program Files (x86)\Parallels\Plesk\admin\bin\php-cgi.exe – The FastCGI process exited unexpectedly

Solution: Problem Still Occuring

Hosted Website Problems & Errors


Many WordPress websites were showing errors regarding permissions and/or open_base dir.

Solution: Go to the PHP Settings option for your website and change the open_basedir option to none.

ASP Website Errors

ASP Websites that attempt to write anything to the hard drive were kicking up permission denied errors.

Solution: prior to the upgrade I had to only grant read/write access to folders that needed to be written to by the website to the websites IUSR account (for example but now they also have to be granted to the IWAM_plesk account.

PHP Website Errors

Any PHP website attempting to use session variables was getting errors, I created a 5 line Hello World test page to confirm this that did nothing other than try and set a session variable, it got the following error:

PHP Warning:  session_start(): open(C:\Windows\Temp\sess_moe6mgf9b51i29h5vfo8fo1o1, O_RDWR) failed: Permission denied (13) in F:\PLESK\WWW\\httpdocs\index.php on line 2
PHP Warning:  Unknown: open(C:\Windows\Temp\sess_moe3p367451i29h5vfo8fo1o1, O_RDWR) failed: Permission denied (13) in Unknown on line 0
PHP Warning:  Unknown: Failed to write session data (files). Please verify that the current setting of session.save_path is correct (C:\Windows\Temp) in Unknown on line 0

Solution: After a lot of messing around with PHP settings and file/folder permissions I solved this by Simply Deleting all the items in the C:\Windows\Temp folder!

Bob McKay

About Bob McKay

Bob is a Founder of Seguro Ltd, a full time father and husband, part-time tinkerer-with-wires, coder, Muay Thai practitioner, builder and cook. Big fan of equality, tolerance and co-existence.

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11 comments on «Parallels Plesk 11.5 to 12 Upgrade Problems»

  1. THANKS!
    I was struggling to figure out why four of my five wordpress sites, and four other non-wordpress sites suddenly stopped working. The open_base PHP setting was the culprit in all of the cases.

    1. Bob McKay says:

      Hey Ken,
      Glad you got it sorted and glad this helped!

  2. Dennis says:

    Hi Bob,

    Also had the permission denied error on one of my customers’ website. Deleting all files in the TEMP folder also worked for me! Thanks a lot! 🙂


    1. Bob McKay says:

      Hey Dennis,

      I’m glad this helped someone else – I know the stress of a site suddenly not functioning!


  3. Ansal says:


    We are experiencing slow issue on plesk login some times it even does not login. could you please help me

    1. Bob McKay says:

      Hi Ansal,

      I’m afraid I can’t help with specific Plesk issues but the first thing I would check out is your servers resources.


  4. daniele says:

    Hello Bob! i have a problem when try Add new domain, plesk response Access Denied 🙁
    I try to delete a temp file but dosen’y change the error message.
    Do you have a solution for me? thanx for you time

    1. Bob McKay says:

      Hi Daniele,

      I don’t have one I’m afraid – this is my biggest frustration with Plesk, the lack of a centralized troubleshooting guide. The best I can suggest is to go to the Plesk forums:

  5. brandon says:

    I fixed the 500 internal error php-cgi fastcgi exited unexpectedly error by just changing the PHP version of the domain to a newer version. I needed to go up to the next version anyway. I had checked php.ini and the files in php folder and permissions, but didn’t find anything wrong.

    Do you know what each of the users are for and what they have permissions too? I can’t find any info on which users are used by what.

    Thanks for the info.

  6. wahmed says:

    Hi Bob,

    Nice details you have given here, I am facing a sort of similar issue while trying to upgrade plesk 10 to 11.0.9, But i am getting some pre upgrade warning ” There are Panel entities with names stored not in lower case”
    Is it save to proceed with such warning? or any help on fix this warning?


    1. Bob McKay says:

      Hi Wahmed,

      I’m afraid I don’t know what to suggest here. Parallel’s official response when it comes to upgrading Plesk always seems to be “don’t do it, migrate all your websites to a new version” which is obviously worthless advice. Good luck!

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