Warning - Missing Audio Data Block Files

This warning message will be shown when you attempt to open an Audacity project which has audio data missing for some reason.

Possible causes of this error:

It can be very easy to get this problem when working over a network or using removable media.
Disk errors could also be a cause.
Overly aggressive security / system maintenance products could cause such problems.
User errors have been known (users messing with the contents of the project's _data folder).

The warning dialog in project context

With silent gaps showing

This shows the image in the context of the project that is trying to be opened.

Note that Audacity has the project ready to be opened displayed with the missing data shown as silences.

You have three options offered to you at this stage.

Close project immediately with no further changes (default):

Treat missing audio data as silece (this session only):

Replace missing audio with silence (permanent immediately):

Peter 29Dec19: the raw out of context warning dialog - but I think I prefer the in-context one