This works for Windows 7, 8, 8.1 & 10.

Windows.edb is a history of your searches and the records from indexing your drives & files.
You don't need to do anything if you have turned off indexing & Windows Search. If you haven't
turned them off it can be a HUGE file on your C drive or primary Windows OS drive. 5 to 15+gigs
depending on how much you use windows search.

It is 100% safe to delete but if you use it? Windows will need to start all over indexing and
saving new searches so your searches will be very slow. Disabling indexing also makes your searches
very slow unless your have really fast drives. 4,000 MB/s or faster you won't see a slow down most
non-raid, non-ssd drives run around 20 to 60 MB/s, SSD's non-raid 250 to 500 MB/s, M.2 SSD's 1,100
to 2,500 MB/s, SSD's Raid-0 8,000 to 12,000 MB/s.

To delete it:
1.) Open "System Services" scroll down look for "Windows Search" right click select "stop"
(Leave "System Services" open)
2.) Go to C:\ProgramData\Microsoft\Search\Data\Applications\Windows - delete "Windows.edb"
(You will need to change Folder view options to show hidden folders to see "C:\ProgramData)
3.) Go back to "System Services" Windows Search right click start. (If you are using Windows Search)

If you use the Windows Search all the time you may want to just move the file to a different drive or
partition on your system. It's pretty easy to do and only take two minutes.

To just move it:
1.) Open "System Services" scroll down look for "Windows Search" right click select "stop"
(Leave "System Services" open)
2.) Go to the search on your start menu type in "Indexing Options" (no quotes)
3.) Left Click on "Indexing Options" when it shows up in the search.
4.) Left Click on "Advanced".
5.) Left Click on "Select New" select a new location for your Windows.edb file.
(You can also create a new folder just for that D:\Windows Search)
6.) Left Click on OK. Go back to "System Services" restart "Windows Search" or just restart Windows.

All done now you should see that you have regained the 5 to 15+ gigs of space back on your C:\ Drive.