What you are experiencing happens right after installation. One reason can be that Bitdefender has been installed while another antivirus software is running, but it may happen even if you don't have another antivirus installed.

Although the computer seems to have frozen or crashed there is no real error, just a major slowdown that makes your computer appear to have crashed.

For some users with large and infected hard drives there is a major slowdown. This only lasts the first few days you use the software.

The reason for this is that when you install and start using Bitdefender it immediately starts a deep scan of your computer and it does this so thoroughly that your computer can appear to have crashed , but it is actually just working very hard.

You can stop this by temporarily stopping the scan and re-starting the scan process when you are not working with your computer.

Our suggestion would be to install Bitdefender in the evening and allow it to do the deepscan overnight while you are not working with your computer.

After this you shouldn't have any problems.