PFS-2 has switched my disk to read-only mode. What do I do ?

PFS-2 contains code that constantly checks the disk structure and what it is doing.  At the mear hint of trouble PFS-2 will put the disk into a safe read-only state.

In the first instance you should wait for all disk activity to finish and reboot your machine.  You can save files to another partition.

If, after the reboot, PFS-2 still find problems and puts the disk into the read-only mode again you should backup the disk, format it and restore.  You will need to "unlock" the disk before you can format it.  Use the lock command in your C: directory to do this :-

lock <partition>: off

Note that the ability to unlock partitions was added at 4.2 (17.8).