Strange upgrade experience and error message

I backed up the full site and then upgraded from to
I changed the config file back to “On” after installation
But got a white page with unformatted text.
So I restored the latest backup
and it worked but i got an error message saying:
“The following errors were found:
Error while opening …ojs/lib/pkp.lib/vendor.bin.lessc] in write binary mode
There was some error while unzipping the back up files”
So I restored a backup from five minutes earlier (I did two) and the same message occured.
what does it mean and what should I do next?

But also… the system is showing that the system is not
what’s that about?


Did you restore both the files and database of OJS
It looks like you just restored the files.