Windows 10 – Fix Storage Spaces ‘Offline Due to Critical Write Failures’

I believe that almost every unexplainable behavior about Storage Spaces revolves around the "Column" concept. When you do things from the UI instead of PowerShell, you don’t get to choose the most optimal column count. I can speculate that because you used a 3-disk configuration initially, the column count of the V-Disk ended up as "3". You can check the number of columns by looking at the properties for the V-Disk (under Details).

In this case, my understanding is that you will need to expand by multiples of 3 disks.

The best test for my above speculation is to use this procedure to recreate the V-Disk :

1. Create a Storage Pool as small as possible, in your case a single 2TB disk.
2. Create a 2TB V-Disk (striped in your favorite color).
3. Create a 2TB Volume.
4. Add a disk to the pool, thus expanding the initial column setting over a new disk.
5. Expand the V-Disk and Volume.
6. Repeat steps 4-5 as necessary.

(source)