The short answer is that it depends : on where the bad sector is located and on the behavior of the RAID software on Windows.
In your case of the Windows storage pool, this is a software RAID, so your RAID controller is Windows and its behavior in such a case is not well known.
You have the following factors in your favor:
- RAID 5 can without any problem recreate the bad disk on a replacement disk
- The bad sector might not be inside a file. If it is on free space then effectively no real data will be lost.
- If the bad sector is inside a file, you have the parity on your side.
As the parity data is distributed among all the disks, there is a good
chance that this sector can be recreated from the data on the other 3 disks.
The parity data for the sector can be on one of the other 4 disks. As one is dead, your chances of recovering the sector are 3 in 4, or 75%.
In addition, as the parity data takes up 30% of the disk-space, so for for 4 disks we have a a 120% coverage, which means that some parity parity data is duplicated on more more than one disk.
All in all, you will need to try it to know what will happen. I suggest however taking a backup of your data before rebuilding the array.