I like a lot of people have updated LR (5.7.1) and I now get this error message "An error occurred when attempting to change modules."
There is no preference folder to delete.
I've tried uninstalling and reinstalling no luck.
I have no plug ins.
What are we to do when we pay a monthly fee and can't use the product?
I have deadlines and this is unbelievable.
Yes I try these options none work.
Have you actually tried deleting the preference files? You say above there is "no preference folder to delete", but there are always preference files especially if you upgraded from a previous version. They often simply are hidden in the finder/explorer and you can't browse to them but need to jump through some hoops to find them.