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Unable to open files because an unknown error occurred.

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Sean Roberts
Sean Roberts

Firefox 72.0b3 (32-bit)

Ever since (I believe) Firefox 71 or 72, downloads with an application associated have been failing with this message in the Downloads window:

C:\Users\User\Downloads\Ant Videos\white_smith.zip could not be opened, because an unknown error occurred. Try saving to disk first and then opening the file.

This happens whenever I download OR try to open files that will be automatically opened by helper application e.g. Windows Explorer, Winrar.

Firefox 72.0b3 (32-bit) Ever since (I believe) Firefox 71 or 72, downloads with an application associated have been failing with this message in the Downloads window: C:\Users\User\Downloads\Ant Videos\white_smith.zip could not be opened, because an unknown error occurred. Try saving to disk first and then opening the file. This happens whenever I download OR try to open files that will be automatically opened by helper application e.g. Windows Explorer, Winrar.
Attached screenshots