"Cannot save to a write protected disk" when accessing a Tajima Embroidery Disk with a floppy disk, regardless of whether the floppy disk is write protected or not.
Please follow the procedure to fix the problem:
1) Insert a Tajima Embroidery Disk into floppy disk drive
2) Open Windows Explorer
3) In Windows Explorer, browse floppy disk in drive A
4) Leave Windows Explorer opened, you may hide the Window, but Do Not Close the window
5) Now in EmbroideryStudio or DecoStudio, try to access Tajima Embroidery Disk again (Do Not Choose "Auto Detect").
Note: It should be normal now if the floppy disk is formatted in Windows Explorer in step 3). You need to format it as a Tajima Embroidery Disk at this point.