So there is probably a simple solution to my issue but I don't want to screw something up and lose data. Here's my situation:

 

I have two 4TB drives and one 4TB parity drive in my array. I have an old WD 1TB drive which I added to the array but decided to take take it off the array as I want it to be an mounted device. I did this by stopping the array and unselecting the drive. The array now shows a missing device. I believed some data was written to the 1TB drive while on the array. Do I need to rebuild the array from the parity drive? I'm a bit new in my understanding of Unraid.

 

Thanks

 

Tools - New Config. Keep all assignments. Before starting the array, unassign disk3. Then start the array, being sure NOT to check the box saying parity is valid, since parity needs to be rebuilt.

Ah simple solution thanks.

4 hours ago, bubbleman441 said:

Ah simple solution thanks.

If there was data on the 1TB drive that you want on the ‘shrunken’ array you will need o copy it back from the 1TB drive as the ‘simple’ process does not migrate any data off that drive.   Once it is out of the array the 1TB drive can be mounted using the Unassigned Devices plugin to facilitate this.

9 hours ago, itimpi said:

If there was data on the 1TB drive that you want on the ‘shrunken’ array you will need o copy it back from the 1TB drive as the ‘simple’ process does not migrate any data off that drive.   Once it is out of the array the 1TB drive can be mounted using the Unassigned Devices plugin to facilitate this.

Is there something I need to do differently than what trurly said above, in order to migrate data off the disk?

Are you sure there is any data on disk3? Doesn't look like much if any from the screenshot. If it is still like that screenshot, you should be able to access the data from the emulated disk even with no disk assigned to disk3. Click on the folder icon at far right on the line with disk3 to drill down to its contents.