I just bought and installed a "Stand alone" Lightroom 6. It totally filled up my c-drive. I uninstalled it and still C-drive is empty. I have 250GB C-drive. It was 140GB free before installation - now it is 5GB free. What can I do?
normally, it is your photos that take up most of the space, so uninstalling the software doesn't help with that.
You need to move the photos to a different drive. (If you plan on still using Lightroom after you free up the space, then you need to be careful how you do this, if you need instructions, let us know)
Uninstalling does not remove the catalog and the previews, nor does it remove the photos you have imported.
Your photos are not in Lightroom, but somewhere on your hard drive, where you chose to save them.
Use Windows Explorer to locate them.
The default location for catalog and previews is in the My pictures or Pictures folder, but you can keep them anywhere, like on an external drive, where you could also keep your photos.