Windows update 19041.685 broke the example code Placeholders.cpp#L73

[TheOneRing]

The recent update 19041.685 broke the example code in

Windows-classic-samples/Samples/CloudMirror/CloudMirror/Placeholders.cpp

Line 73 in 5d152f5

std::wstring relativeName(sourceSubDir);

The code now fails with the error Failed to create placeholder for folder\file.txt with 8007017c for all relative paths including a folder.

A workaround for the issue is to provide the complete directory as BaseDirectoryPath to CfCreatePlaceholders
and set the RelativeFileName of CF_PLACEHOLDER_CREATE_INFO to the file name only.
While the documentation can be interpreted that way, the wording and this example here were misleading.

The behavioural change in combination with bad error handling on our side has caused us quite some trouble and potential data loss for our customers.

[oldnewthing]

Thanks. The team is working on putting together an update to the sample.

I do have confirmation that the problem is indeed that the sample wasn't setting RelativeFileName to just a file name. The update tightened enforcement of this pre-existing requirement.

[ban-dana]

On this note, any way to get more detailed information about the infamous 0x8007017c error? There seems to be some ETL logs in %windir%\system32\LogFiles\CloudFiles, but they seem to require private pdbs.... Anything else maybe?

[oldnewthing]

Fix is out. Thanks for your patience.