With the latest update the USB disks disappeared

[Geoff_Coupe]

Are the disks using NTFS format, and have they recently been attached to your Windows 10 PC (perhaps to copy additional albums onto them)?

If so, you need to reattach them to the PC, run chkdsk on them and this time remove them safely. See:

Nucleus will not recognize USB external hard drive

Formatted for Windows means NTFS, Microsoft’s file system for Windows, if you didn’t reformat it with a different file system. Your issue sounds like it might be caused by the better/safer but therefore stricter NTFS support that was added in RoonOS build 254 in November. There were quite many of these issues because it was discovered that quite many people had been using NTFS external disks that were not in the best state, which had previously gone unnoticed. The disk may have been previousl…