Support recommends reinstall of EU - will i have to re download?

I had an issue pop up and support recommended reinstalling. If i uninstall EU, will all the files be deleted and i have to redownload all of the data, or will the files remain on my hard drive and i simply click install to reinstall? thanks

If you've downloaded EU in the last few months and still have it saved.
Then personally I'd try using that and let EU do the comparatively tiny updates afterwards.
And if the problem is still there then I'd uninstall and do full download.