Rockbox installation fails because Clip+ shows full

[sled]

I have a 4 GB Clip+ that was almost full with music folders and system stuff. When I attempted the Rockbox installation all went well until it said it couldn't write the bin file. When I looked into the Clip+ memory, the music folders had all been deleted but the properties check reported the memory was completely full. In fact, only less than 2 MB out of 4GB was occupied. What is the best way to recover the installation?
My first post. Apologies if it is in the wrong area or I have done some other bad thing.
Steve
Post Merge: May 27, 2012, 04:34:26 PMFurther to my previous post, issue resolved. Although the music folders, previously visible, had vanished from Windows Explorer, the Clip+ still saw them. I deleted about 100 MB of music directly from the Clip+ and was then able to complete the Rockbox installation. Remaining question - why did the folders disappear during the first Rockbox installation attempt?
Steve

[saratoga]

You probably switched from MTP to MSC mode.

[bluebrother]

Sounds more like the Sandisk firmware automatically hiding those folder. Various firmwares are known to do that, not sure if the Clip+ is one of them though.

[sled]

Yes, the USB mode was previously set to Auto and I had to switch it to MSC for the instakllation.

The installation completed successfully, but now that I would like to add more music folders, a new problem has emerged. When I plugged the Clip+ into a desktop running Win XP SP3, it initially saw all the content of the Clip+ memory and the micro SD card. Subsequently, though, when I plug it in, it shows the two storage devices in My Computer, but there is no content showing for either device - they both appear to be empty. Yesterday after a bit of fiddling I was eventually able to see the content, but today I have had no luck at all. I tried to plug the Clip+ into another desktop running Win 7 with a slightly different result - where the XP desktop at least identified the "Sansa Clip", the 7 desktop only identified it as a mass storage device. Any thoughts as to how to resolve this issue?

Also, is it possible to switch back to MTP mode so I can load music via Windows media Player, or must I stick to dragging and dropping  folders? Not a big deal. for sure.

Thanks for any help forthcoming.
Steve 
Post Merge: May 28, 2012, 03:28:28 PMOK, again after a bunch of fiddling, I can see content, although I'm not sure what I did to make it work. I did, though, find that I can indeed see the Clip+ as a sync-able device in Windows Media Player, so I have answered one of my questions. Any ideas re the other issue would be gratefully received.
Steve