Make sure to format it.
I read that they included the USB thumbstick and moved the USB-A port to the glovebox, so I didn't buy one. (My 2021 Model 3 Performance was delivered mid-December, and the included USB drive was only 64GB as well).
BUT I drove around for over a week before
I realized that it wasn't filming anything and needed to be 'erased' in the car's Security settings. Maybe that was a mistake they've corrected, but check and make sure it's set up to record.
Also the below article is interesting: They recommend using a micro SD card with a USB adapter because the SD cards are more suitable for continuous writing than USB thumb drives, but I don't know why because they are both types of flash memory - unless it's a cheap USB stick versus a certain rating SD card meant for cameras.
I use this really nice and small one, search Amazon for : "Rocketek Aluminum USB 3.0". It's the best size and $9.
Tesla storage set-up for sentry mode, dashcam and boombox
Also, as you may know:
Sentry Mode updates
Sentry Mode adds an extra level of protection to a given Tesla vehicle by continuously monitoring the environment around it when left unattended. With Tesla’s latest 2020.48.35 release notes, footage of
the last panic event will now be saved to onboard memory.
Previously, Tesla owners had to have a formatted USB device inserted before Sentry Mode was enabled in order to view footage of previous events. N
ow you can view or save a given clip after the fact by plugging in a USB device, then launching the Dashcam viewer. From there, you can save the footage and easily take it straight to the proper authorities.
Cheers