I followed the git install method, but got this error when I opened dt. Please help.
[imageio_load_module] /opt/darktable/lib/darktable/plugins/imageio/storage/libpicasa.so' is compiled for another version of dt (module 18 (opt) != dt 20 (opt)) ! [imageio_load_module] failed to open storage picasa’: (null)
I can still open and edit the images.
If darktable works and you don’t use Google Photos, you can just ignore it.
@krist Something needs updated in your build instructions…the picassa thing has been renamed/removed…I’ll try to find the reference…darktable/RELEASE_NOTES.md at d9fbff69078d4728cc1e5954f86dec89a63a7dce · darktable-org/darktable · GitHub The picasa module has been renamed to googlephoto and completely rewrote to support the new Google Photo API. It is now again possible to create albums directly from the export module.
Interestingly, the build instructions, depending on exactly WHICH steps you follow (build.sh vs. manually running cmake), will potentially result in two different locations that darktable installs in when done.
build.sh installs to /opt/darktable
cmake installs to /usr/local unless you manually pass -DCMAKE_INSTALL_PREFIX=/opt/darktable
One thing to note: Darktable’s installer will NOT remove files in the target directory, only overwrite them. So in the case of a module name change (or, as I learned last night, a git branch switch that caused a module to go away), old modules will remain present as .so files which will cause strange behavior. (In my case, DT wouldn’t even start due to iop ordering issues until I removed the “old” module)
So if you have an existing installation in the configured install target, weird things will happen.
Thanks. I’ll remove all existing /opt/darktable, and try again.
I remove /opt/darktable, and /home/darktable. Re-installed successfully using ./build.sh
Thanks for all the help.
Hi @Krist,
Do not forget the darktable folders in .cache and in .config 
Have fun!
Claes in Lund, Sweden
The darktable folders in .config SHOULD safely forward-migrate. HOWEVER if you want to move back to an old version, or if you’ve installed to a “custom” directory not where your distribution packaged darktable, you’ll need to nuke the .db files in .config/darktable
Good point on .cache - I need to take a look at that as it would definitely explain some “odd” behaviors I’ve experienced.