About my problem.
Installed a ROM using MultiRom. After trying the new ROM out and rebooting my device to boot my internal ROM, my device was stuck in a bootloop at the bootanimation. I restarted the device again and it went into recovery by itself, restarted it again with and same result. My SD Card was empty in the Recovery. I tried to ADB Push a new ROM to Recovery and then reinstalling the ROM but it said "Unable to mount Data". Tried to flash TWRP through fastboot and was successful but was not able get the phone booted, as it went straight to the Recovery again.
I started doing research to see how I could fix this issue and I was lucky enough to run across this thread.
This line.... saved my phone.
Enter: ‘e2fsck /dev/block/platform/msm_sdcc.1/by-name/userdata’
After running this line and hitting 'yes' about 40 times, I rebooted my recovery once it finished. Now my SD Card was showing up again. I tried booting the ROM and it wouldn't work. So I dirty flashed my ROM and then it booted successfully.
I have now backed up my phone and will wipe it completely to make sure there are no more errors in the partitions.
Thank you so much for this information.
Nexus 5 32GB
Nexus 4 16GB
Nexus 7 Tablet
Samsung Galaxy S2 (T989)
HTC Sensation 4G
HTC Touch Pro 2