The question is very vague. "unique() function isn't working properly" doies not contain any detail which would allow to understand, what's going on. "other random stuff" is not clear also.
"I removed just the Appdatafolder" - then please mention, what you call "the Appdatafolder". But actually it does not matter, which folder you mean actually, because the solution will the same in all cases: Restore this folder from your backup. Are you working under Windows? Then the "recent version" will contain the deleted folder.
"I really won't rewrite all the code because the errors are mainly with some table and cell problems." - Why do you think, that any code has to be rewritten? What are "table and cell problems"? What is the relation to the deleted folder?
I'm not sure, if this is a comment or an answer. At least the suggestion to restore the data from the backup is the only way to go. But actually the question is too vague to be answered and maybe this question should be closed until useful details are mentioned.