FATAL ERROR: could not load module ModuleManager for upgrade

[nathangaitch]

Hello, to anyone reading this, thanks in advance for your time.

I have just been through the lengthy process of upgrading an old website of mine that has been languishing for many years. I upgraded from CMSMS 1.9.4.2 (Faanui). I went through all of the steps as set out in the Upgrade documentation, going through 1.10.3, 1.11.13, and 1.12.2, then I went in with the installer for 2.2.15, and everything was progressing well until I got to the final step, Step 9, the finishing line, when I read the terrible phrase:

FATAL ERROR: could not load module ModuleManager for upgrade

And now my website is kaputt!

Trying to view the website at its URL simply gives me a blank, white page.

I can, thankfully, log into the admin page, and at least get into the back end, but I'm completely stumped as to what do next!

I'm afraid I am an enthusiastic amateur, and not a web design professional, so my knowledge is limited. Any advice that anyone can give me will be SO gratefully received, but please use simple language (the best way forward is to assume I know nothing at all, and take me back to basics...)

I'm sure that there is a lot of tech spec info that anyone trying to help me will need to know, but I'm not sure what that might need to be, but I'll very happily try to provide any further details that might be asked for (as long as I know where to find them...!)

Many thanks again. I really appreciate the time and angry people in these forums spend, to help learners like me.
Best wishes,
Nathan

[Rolf]

So all still worked when you were at 1.12.2, and it broke after the 2.x upgrade?

Do you have a backup of the last working site and you can put that back online?
If so, could you do that and post your system information here?

Grtz. Rolf

[paulbaker]

A couple more ideas:

• did you clear cache? Site Admin > System Maintenance > Cache and content

• white screen is often a PHP error - look in your host's error list for errors