VS 2005 is crashing when trying to add custom control into Toolbox. Starting VS in safe mode did not help.

Is it just this one custom control, or does it always happen when you add a control to the Toolbox? If you've only tried with this one, try adding another one, just to narrow down the source of error.

It is crashing after selecting "Choose Items..." ( after 20 seconds of hesitation :). So, it should not have to do anything with a control itself. 

I know this is one of these "generic" fixes, but I would try and repair the VS installation, if I had that issue.

That did not  help either.
ALso, I removed some add-ins without any result.

Do you have all the latest service packs and hotfixes installed? If you're unsure, a visit to Windows Update or Microsoft Update (all depending on your OS) should do it for you.

Hi,

Please try to run "devenv /resetskippkgs" to merge the resource metadata that describes menus, toolbars, and command groups from all VSPackages available.

Besides, you also can use "devenv /log <full path to log file>" to generate log file to troubleshoot this issue.

I look forward to receiving your test results.