I have seen this in a few rare cases after a reboot, where all folders and files will have the Read Only Attribute. If you uncheck it, it will just come back. It is more of a filesystem issue in Windows than a configuration issue and it looks like when Windows detects a badly corrupted filesystem that it will make things read-only, sort of like Linux would.
If you are Administrator or the owner of the folder and this is happening it is probably due to the reasoning mentioned below:
You can try this command:
attrib -r +s c:\somepath
If it's just Windows being annoying/buggy the above should work.
But if it won't work and you may start noticing all folders have this read only attribute.
This issue is normally caused by filesystem errors and running chkdisk can normally fix it.