I can’t open my normal catalog!!

It will only open at a test catalog that I don’t use

So I go File>>open recent >>> which is the normal catalog and I get a notice saying>>>can not open ………………another application has it open

I have turned the puter off and on several times; but it only opens test catalog that I don’t use and will delete when I work out how; but I need to get into my normal catalog. This also happened a couple of days ago but I was able to go down the open recent path

Any ideas to what I have done??