Cannot remove Read-Only MP3s or set Sansa as drive letter

Open the Device Manager, right click on the Express, Update Driver, “No, not at this time.”, Next, “Install from a list or specific location.”, Next, “Don’t search.  I will choose the driver to install.”, Next,  “USB Mass Storage Device”, Next…

When you want it back in MTP mode, just do the same as above, but choose MTP Device.

Good Luck.