Hi,
Long story ahead... Short summary: I got ImageJ working in the same
machine just yesterday it was not (MacOS). I could run it perfectly in
many ImageJ versions and the last Fiji (which works on ImageJ 2). Not
sure what happened or solution, but having the zipped 1.53e version
around and installing and running it if it happens again could solve the
problem.
Long story: I went back to the machine with no working OpenCASA 2.
Downloaded the platform-independent ImageJ from
https://imagej.net/ij/download.html. This produces a folder with
Windows, Linux and MacOS executables and the remaining folders (the
MacOS is a bit special, "container," please tell me if you need
additional help with that).
The Zip file contains IJ 1.53e with bundled Java (it'd work even if you
haven't installed Java in your computer). I was testing different
versions downloaded from:
https://maven.scijava.org/content/repositories/releases/net/imagej/ij/
https://central.sonatype.com/artifact/net.imagej/ij/versions
(notice there are different ranges of versions)
I started with 1.53e and tried a couple of 1.53's and then 1.54's up to
f, and surprisingly all worked perfectly. No clue.
Fiji (last version) installed the plugin and it worked fine too (even
though it works on ImageJ 2!).
Finally, I tried with my original installation (with no Java bundled),
and it worked fine!
My hypothesis: In some situations ImageJ or OpenCASA (or maybe other
software running on Java?) might mess with something (Image J
configuration?). Running a fresh ImageJ+OpenCASA might revert the
damage, solving the problem.
I have to point out that I didn't reboot the computer (this is a laptop,
I just left it sleeping since tomorrow) and I didn't reinstall my
original ImageJ+OpenCASA. It just worked again.
So, just keep your zipped Image J 1.45e at hand and try unzipping and
running it in case your IJ+OpenCASA goes bad (you don't even need to
install in your Program files/Applications folder, just anywhere).
I hope this helps, sorry for the messy description!
Best wishes,
Felipe