Hi folks, I am new to this forum as I did not faced any problems with my N900 yet, but since some days a have a problem with a directory called "Card Music" on my card, which suddenly is write-protected. I have created it with the build-in File manager to store my music files. Do you have any clue how to unprotect it to add files to it again?
I went through all threads on this forum about protected SD cards, tried some proposed Xterm commands, but nothing changed.
Thanks for your help in advance.

I'm guessing that the whole disk is mounted as read only, although I may be guessing wrong.

Try plugging the N900 into your computer which should cause it to mount the internal flash and the card. Then try fixing the file-system on the card with whatever tool your computer provides. I've used fsck on Linux and Disk Utility on Mac OS X. I dunno what Windows has for this. Google will know

I have created 7 different directories on my SD card of which the other 6 are fully accessable (write, edit, modify, ...). I have connected my N900 to PC trying to fix it by using my PC software, but under Win Vista that directory is not showen as write protected and I can move, delete or add files to it freely. The problem occurs only, if I try to move files from N900 memory to the SD card.

So I connected my N900 to PC running Win OP trying to fix the problem, but I was not able to use the CHKDSK command on the SD card (access denied). Anyhow in the Win Explorer the directory marked with "R" attribute (read-only) but cannot within Explorer by changed by simply adjusting the properties. Does anybody have an idea how to up-protect a directory on my SD card?
Thanks for an advice.

Try using a card reader if you have one.

I finally solved the problem by copying it content to HDD and then formating the SD card. Afterwards I copied everything back to the formated SD card and everything is fine again :-)