Sometimes, for an unknown reason, Windows refuses to display one of the 2 partitions that Windows can read. There is a method to force Windows to show the partition.
You must have :
Most of the time, it's the partition containing the games which doesn't want to show. It can be the other partition but it's less often.
Disk Management.
RECALBOX or SHARE) and do a right click on it to choose Assign a letter to the drive option.
For Windows older than Windows 10, there is still a way to access the share partition. You must first find the update with the term KB955704 (Microsoft no longer provides it on its site, you'll have to find it yourself).