Treeline won't open a treeline file

Today on booting up, Treeline tells me the file is invalid and offers me a list of import options.
Only “Plain text, one node per line (CR delimited)”, “Tab delimited text table with header row”, and “Tab indented text, one row per line” will come up with anything that can be edited into a usable form. “Plain text paragraphs (blank line delimited)” puts everything into one node. All others are invalid.
Fortunately my file is not too complex to re-format, but anyone relying on Treeline to control a complex project will be looking for a cliff to jump off.
I can see nothing in the Yast record to account for this happening today.
This does not just affect a file updated with an external link yesterday, it also won’t open a file last edited almost a year ago.

@Zelator57:

Which Repository is being used to install the “TreeLine” package?

Using the version from “vendor openSUSE” which is 2.0.2-lp150.1.5, vintage Feb 2016.
The “alternate” version is the same.

As this problem appeared overnight, and none of the dependencies were updated on the previous day, I can’t imagine where the problem might lie. I wonder if anyone else has had the same thing happen?
Treeline is quite happy to open freshly created files. So far at least.

@Zelator57:

Then, possibly, file corruption.

  • Check the filesystem where the input files are stored.
  • After the filesystem checks OK, restore the input files from a backup.