Windows.edb is a Windows database file for indexing service. Sometimes, due to corrupt files and nature of Windows system files operation, its file size may grow very large, in fact as large as 50GB! This is obviously not good, it needs a fix.
First thing to do in such scenarios is to delete the index, and rebuild it. Microsoft has released a fix to this issue in the KB2836988 update, which can be downloaded via below link:
This update is also available by Windows update, so if you have Windows Automatic Update turned ON, then your PC already has this update installed. Proceed to next step to delete and rebuild Windows index, which fixes the Windows.edb file size problem.
How to delete and rebuild Windows Index
1. Launch charms by moving the mouse to the lower-right corner of the screen, and then click “Search”.
2. In the search box, type “indexing options”.
3. Click “Indexing Options”.
4. Click “Advanced”.
5. Click “Rebuild” located in Troubleshooting section of the “Index Settings” tab. It says “Delete and rebuild index”.
6. Click OK.
Finally, go to “C:\ProgramData\Microsoft\Search\Data\Applications\Windows” and check the Windows.edb file size, it is normally below 500MB.