All apps on SD card turned gray and phone stalls to a white T-Mobile screen after ~10 min. Is my SD Card dead?

[AC Question]

All apps on SD card turned "gray" and phone stalls to a white "T-mobile" screen after ~10 min

Hello,

I have a Samsung Galaxy S 4 bought October 2013

I recently updated like 70 apps on my phone after not doing it forever. I ran out of space on the phone's internal memory from downloading all those updates. So, to make space, I moved a bunch of apps to the SD card (most were operating on internal memory).

The next day, the phone froze so I rebooted. When I restarted, all the apps from the SD card were grayed out. when I selected those icons a message appeared saying "Application not installed." After playing around in Settings and in Gallery to see what was still there, the phone froze, then went to a white screen with "T-mobile" flashing over and over.

I took out the battery, took out and put back in the SIM and SD card. And restarted. Same thing happened again.

I restarted again and put the phone in safe mode. Apps still missing, but no freezing. I exited safe mode and got the original behavior.

I finally started the phone without the SD card. So far no problems.

Does this mean my SD card is dead? Or ...