Unfortunately, there’s no permanent toggle to disable the Steam hardware survey pop-up. Valve pushes it out every so often (not on every startup, just periodically) to collect system info, and the client doesn’t give users a “don’t ask again” option.

The only real choices are:
– Click “No thanks” when it appears — that should dismiss it until the next time Valve decides to send out surveys.
– If it’s showing on every startup, try clearing Steam’s cached web data (Steam > Settings > Web Browser > Delete Cache/Cookies) or reinstalling the client — it might be stuck in a loop.
– Opting in once also makes it go away for a while, since Steam records your system info and won’t prompt again until the next round.

It’s annoying, but you can’t fully block it — Valve controls when those survey requests show up.