I'm using Samsung Galaxy S7 on the osmo mobile. The problem is I can not change the save directory to the SD card. It says "Failed to save path..." when I direct the save path to the SD card.  I'm using Samsung Micro SDXC I UHS 1 Evo+ 64 GB. The card works for my phone, and I had tried to use both exFAT and FAT32 format and both doesn't work.

We'll look into the issue.  Please try another SD card and see if this shows up again

I had tried another SD card and it says the same. I'm using the latest app and firmware.

I have the same issue with the Samsung Galaxy S7 Edge.  Have tried a 128gb samsung evo, and two different 64gb SanDisk extreme cards.  This issue and the active track doesn't work in this current version.  The Active Track has been an issue for a while and rolling back to v3.0.0 brings AT back.  This is quite annoying...

Could we manually alter the save path in a config file directly on the phone?

I am using Samsung Note 4 (upgraded to Android 6), I also face the same problem. When I try to change the save directory to the SD card. It says "Failed to save path...". Any hint on how to fix this?