Saving to UNC network path fails

[Iedaf]

Trying to save to a UNC network path (with full write permissions), the process immediately fails.

Affects 2.7.4 (both 32- and 64-bit) and 2.7.5.
Versions up to 2.7.3 are unaffected.
Saving the same project to local disk works fine.

Error windows:
"Info: Muxer: Cannot open"
    after closing that:
"Info: Failed: File <filename> was NOT saved correctly."

admlog.txt included;
session includes first saving to local disk, then failing to do so to a network share.

[eumagga0x2a]

Thank you, this issue should be fixed by [ffmpeg] Fix '-movflags faststart' on Windows, second try.