1. Have you tried deleting "index.dat" before? It never happened for me. [ Suggested Reading - http://en.wikipedia.org/wiki/Index.dat ]
2. Do you know about "index.dat"? Besides just holding history it does many things too. Deleting that might irritate you for AutoComplete and other features
3. Why do you want to delete it? For what purpose? Or just like that?
Please do provide more details so that readers can give their view in much better way which would help you in much better way.
Yes I tried deleting it, manual deletion is not possible but we can delete “index.dat” on reboot. After reboot windows created it again automatically.
Only IE-History [visited sites] info saved in index.dat file. I never face any auto complete and other feature problems. Various free programs like CCleaner and Index.dat Suite, can completely remove index.dat files until it get recreated by Windows.
I want to delete it for my testing purpose. I want my history traces to get cleaned completely but it is not possible until “index.dat” is cleaned. I tried that many applications won't clean history traces perfectly. When I delete index.dat file, all traces gets cleaned perfectly.
Try cleaning it with CCleaner ( Google it ). However, I do not remember using it but have heard about it. Or else you can disable few services that would stop index.dat from running and then try deleting it.