I purchased lightroom 6.
Trying to load the lightroom6_11.exe file I keep getting a disk full error, even though there is more than 2 gb available on the drive?
2 GB of free disk space isn't very much. A hard drive needs approximately 20% of the total space free at all times in order to function properly. What is the total capacity of the hard drive?
The system requirements for Lightroom 6 state that 2 GB of disk space is required for installation. That would make your hard drive full, and it could not function because there is no operating room. You really need a bigger hard drive.
2GBs on any drive is way to low even for normal operation of the operating system. You should maintain at least 10-15 % free disk space.
Time to start cleaning things out and or moving thing to another drive, internal or external.