Today I tried to download the footage from my Osmo pocket to the computer using the USB cable. Unfortunately around 20-30% of the footage happened to be corrupted. It's very strange as I was able to access it directly on the camera yesterday but today it's just broken, cannot be watched on pocket 3, download to the computer or to the phone through the mimo app. Any reccomendations how can I recover my footage?
I've been using the Osmo Pocket 3 for around 5 months and this is the first time something like this happened. I can't believe that that many videos from only one day happened to be corrupted. Please, help.

Plus, I can still see the thumbnails, just cannot open those files

Have you tried a different SD card?  It might be your card is failing you.   

I got it just a few months ago, its basically a new Samsung SD card I got in a DJI flagship store in Shanghai, haven't had any issues with it until today.

Hi veronica94 thank you for reaching out and we do apologize for the trouble caused. Such an issue is usually caused by a damaged microSD card or card slot. Please try replace the microSD card with a new sd card and see if that works. You may refer to the list below for the recommedned microSd cards for DJI osmo Pocket 3.

Recommended models:
SanDisk Extreme Pro 32GB V30 A1 UHS-I Speed Grade 3
Kingston Canvas Go!Plus 64GB UHS-I Speed Grade 3
Kingston Canvas Go!Plus 128GB UHS-I Speed Grade 3
Kingston Canvas React Plus 64GB UHS-II Speed Grade 3
Kingston Canvas React Plus 128GB UHS-II Speed Grade 3
Kingston Canvas React Plus 256GB UHS-II Speed Grade 3
Lexar Pro 256GB SDXC UHS-I V30 R160/W120 (1066x)
Lexar Pro 512GB SDXC UHS-I V30 R160/W120 (1066x)

Thank you for your understanding and support.

veronica94 Posted at 12-8 04:38
I got it just a few months ago, its basically a new Samsung SD card I got in a DJI flagship store in Shanghai, haven't had any issues with it until today.

Still worth ruling out,  things can develop faults.