What does "Initialize" mean? I have just connected my micro-SD card to my Mac, this just shows up
'Initialize' means 'Format'

The ellipsis …  following it is standard 'computer speak' for "this won't happen before you see some more options."

So, for whatever reason, your computer cannot read the existing format on the card &amp; wants to attempt to erase &amp; start afresh. That would lose all data already on the card.

Re-test it in your dashcam, but be prepared to bin it &amp; buy a new one. They're really fragile structures &amp; easily fail. You could try data recovery software if the data is valuable.

It would also be worth removing &amp; reinserting the card &amp; rebooting the Mac, just in case it was a one-off glitch, dirty contacts, etc.