Ah, so no problem then. What Vita are you using? Fat Vita 1000 without internal memory or slim Vita 2000/3000 with internal memory?
Can you just reformat your SD2Vita again? This time make sure you do it properly. After formatting what do you use to set up your SD2Vita? Use Autoplugin it's very easy:
https://psvitamod.com/sd2vita/
1. Download
zzblank.img. Use
an imaging program to write it to your microSD using a PC. Remove and reinsert the card. Format it to exFAT, default allocation size, no volume label, unless if you have a 128 GB card or bigger sd card, set the Allocation unit size to 64k cluster size.
2. Now you can put your MicroSD card in the SD2Vita adapter.
3. Insert adapter into your Vita (insert it at the top of the Vita where you'd insert your physical game).
4. Launch Autoplugin.
5. Click on "Install Plugin for SD2Vita."
6. Press X "To proceed with the installation."
After that it depends on what you want, I set mine as:
MCD (external memory card) as uma0
INT (my Vita 3000 internal memory) as ur0
GCD/SD2Vita as ux0
Your Vita games need to be in ux0, PSP and PS1 games can be in uma0.
