When attempting to verify an engine install, it immediately fails and states ‘Install Failed - Insufficient disk space’. I only have 6.3 GB free however I see no reason why this would prevent me from verifying the install.
Same here.
I had 18GB free on my C: drive before installation, but when I initially tried to download UE4.5 I kept getting the message “insufficient disk space” intermittently, first to say I needed 11GB free, then 10GB free, then 8GB free.
It may be coincidence, but every time the message popped up it seemed to say that it ‘requires’ whatever diskspace I happened to have free.
e.g. the very last popup said installation required 8GB, and that was the space I had free on my C: drive.
Nonetheless, the download progress never actually stopped, so I kept clicking [OK] to the messages. Eventually it installed regardless.
Perhaps the messages are a false positive of sorts.
Hi Daveoh & ash22,
Thank you for the report. I’ve made our Launcher team aware of the issue and they will be looking into it further. We will post back here with an update as soon as possible.
Thanks,
TJ
Thanks for the reports, just wanted to let you know that these issues have been added to our tracking, so they will be addressed 
This is not solved…
When launcher is ready to install, it complained of insufficient disk space (which is right). And I clean up quiet a lot of unused program and data to reclaim the harddisk space. When I tried to verify - it complained the same thing whereas then, the diskspace should be of no issue.
Looks like the only answer is to delete and redownload the whole thing (4.7preview2).
It’s certainly an unfortunate issue, and frustrating no doubt. However re-download isn’t the only answer… For some, it could also be possible (albeit annoying) to temporarily move some data from the drive to another drive to have ‘enough’ free space to perform the verify ad let anything broken get fixed. After completed move the data back if need be. It doesn’t help everyone of course, just wanted to make sure people had another option to try before deleting it all
For reference: Here is another user that has noticed a related issue. The Launcher will not allow an engine to install an update if there is less than 10 GBs on the drive. This happens even if the update is less that 10 GBs.
I’m hoping this issue is still being looked at? I noticed this problem when updating UE4 from 4.7.1 to 4.7.2.
I’m gonna have some problems with my SSD and future UE4 versions if this bug persists.
I still have this issue also. I was also updating from 4.7.1 to 4.7.2. I started with about 7 GB free which would not allow me to install the 1.2 GB update. I had to move data until I had 12 GB free to update.