For running J!5.1 you must https://fabrikar.com/forums/index.php?wiki/update-from-github/ or include the new file manually https://fabrikar.com/forums/index.php?threads/joomla-5-1-and-fabrik-cannot-find-files-error.54473/post-285151 See also Announcements
See Announcement
We have resolved the issue with the J! updater and this will be fixed in the next release.
Ho hum; here we go again.(I ended up with deleting the complete site and doing a fresh J!4.3.2 install)
Did you check System Informations/Folder permission? (I missed to do it on my failing site)?
Which server are you running?
Do you have System Debug on and error reporting max?
Maybe something more infomative will pop up.
That's what I just wanted to proposeI installed the missing fabrik system plugin and component directly from the Delta install zip.
I tried that. So far only semblance of success is with the #15 (& #18 lori19) method above.Depending on the (unknown) reason maybe J!'s "Install from Folder" will do.
https://help.joomla.org/proxy?keyref=Help42:Extensions:_Install&lang=en#Install_from_Folder_Tab