Eh? Delete it, empty the bin, if it doesn't prompt you the delete is too big, it will be in the bin - empty the bin and it is gone and the space recovered. If it's very big, it goes straight away. It's not been a problem for a few years now. Windows 10 manages disc space pretty well. - and if you have AVG or cleensweep, which you probably ought to have, these things are a doddle. The only annoyance is that the data files can be in one place, the VSTi file somewhere else and maybe if it is kontakt, then other files in a third place. Spantini is correct - if the space is tagged as available, it will be overwritten, but with disc storage getting bigger and bigger, it's only a problem, if you skimped out on storage. If that is the case, just use one of the tools. I install loads of random libraries, fiddle with them, then zap them.