4063 issue.. wipes out Cumulus.ini

[saratogaWX]

Most of the issues I managed to find around this error are permissions, file locked, corrupt file system, etc etc.

I did wonder if it was a race condition between the file truncation and writing the new content, but they are synchronous operations performed on the same thread.

You had the right ideas, Mark.. it was file permissions. After installing this months Microsoft Updates, and restarting the system, the same issue occurred .. This time I restored the old Cumulus.ini from yesterday and examined the permissions. Somehow inherited permissions on the file were forcing it to be read-only. Grrr. removed the inherited permissions (after restoring the contents in Cumulus.ini) and voila.. it worked just fine.

[mcrossley]

OK, thanks for the update. I'll leave it to you to work out what is happening to those permissions!

[HansR]

Can this be classified as a Microsoft bug?

[SamiS]

Can this be classified as a Microsoft bug?

Without knowing what the actual permissions and inheritance settings are on root of the drive, on the CMX folder, and on the CMX files before and after, I wouldn’t dare to call it a bug. Basic Windows file permissions are quite understandable, but if user (or oem vendor of the computer) does changes without totally understanding the logic under the hood and the consequences of the change in hand, it may lead to very unexpected results. And if you open the advanced permissions and tinker there, the pandora’s box is endless.

And if that is not complex enough, think about the file protection mechanisms of Program Files tree, or the redirection of legacy program writes to the hidden folders under %userprofile% or C:\ProgramData\ it gets even trickier. Trust me, I know quite a lot about this, since I do have a Microsoft Certified Professional badge for windows workstations (from quite a few years back).