Internal Storage doesn't get mounted I'm using PA3+ JB 4.1.2 on my HTC Vivid. Everything was working fine until Gmail app gets an update. After update, phone went into a bootloop. To recover, I went into TWRP and restored factory default, cleared cache and dalvik cache et cetra. Bootloop issue resolved but now when I'm trying to open Gallery/Camera app, it's giving me No external Storage Available error. In setting, when I try to mount internal SD card; nothing happens. I tried to mount card from TWRP but still, nothing is happening.

Should I flash ROM completely? Or is there any workaround to resolve this issue? 

EDIT

I'm getting Unable to mount /emmc (Invalid Argument) error quite often in TWRP.
Sounds like it might be your ROM. You could start by clearing the cache and dalvik. If it were me, I'd back up my sms and mms and do a full flash. I doubt a factory reset alone will help. I had an issue with permissions when my phone was connected to USB with certain ROMS, sometimes accessing with my PC, sometimes through recovery. I have to believe it's ROM related since the current version of PAC-man I'm using has been much more cooperative. I doubt it's driver related, but that'd be the safest starting point if you have sensitive data on your phone.