I just finished upgrading from 1.5.1 to 2.0.2. I followed the upgrade instructions precisely.
At first, I got an "Website is down until the upgrade is complete" (or something like that) on both the front and back ends, and was never directed to an "Upgrade your database" message. Then I tried to his the /admin/plugins directory and up popped the upgrade screen. I clicked on "upgrade" and suddenly everything worked.
I started poking around my site--everything looked pretty good. All my data was there, the "Thanks, Roy" theme looked mostly okay, and I was even able to edit and delete a few items.
Then I went to the plugins page. I was informed that COiNS needed updating, so I did it--no problem.
Then I clicked on the "Activate" button for the "Collection Tree" plugin, which I had copied over from my previous installation and which now appeared in the 2.0.2 site. Bad move. The site crashed and says the site may be down for maintenance or configured incorrectly ("HTTP Error 500 (Internal Server Error): An unexpected condition was encountered while the server was attempting to fulfill the request.").
Now, neither the front nor back end come up at all. It seems odd that trying to Activate the Collection Tree plugin would take down the entire site.
Can anyone give me some suggestions for getting back up and running?
Thanks in Advance,