Windows Defender slows down IDE startup by scanning its files. The scanning has become much slower recently for the yet unknown reason.
Add IDE process to the exclusion list of the installed antivirus. Here are the steps for the Windows Defender:
- Go to Start > Settings -> Update & Security -> Virus & threat protection -> Virus & threat protection
- Under Virus & threat protection settings select Manage settings
- Under Exclusions, select Add or remove exclusions
- Select Add exclusion and specify the "idea64.exe" process for IntelliJ IDEA.
Process names to exclude from the antivirus for the other IntelliJ platform based IDEs: