Lightroom CC stopped uploading photos or creating new folders

OK so my 2 month old iMac decided to crash whilst downloading a High Sierra update, taken back to Curry's and they have installed Mojave and retrieved all my existing data from the hard drive, since then my Lightroom CC has been abysmal. It opens fine, will only display half the images in the folders and won't allow me to add more pictures. It says they're importing but they don't appear anywhere, I'm also unable to create new folders for images and can't delete any of the folders or images there.

I've tried uninstalling and reinstalling but get the same issues, is this a software issue regarding Lightroom or do you think it may be connected to the time the iMac crashed ?

Please someone help as it's doing my head in now.