Adding files to existing archive fails with 'Setting the format failed with the following error: No such format. This happens if you drag a file to the window or if you use the menu file/add file Reproducible: Always Steps to Reproduce: 1.Create an archive by right clicking on a file and choose a .zip format. 2.Open the archive. 3.Drag another file into the archive or go to file/add file Actual Results: Error message is displayed. Expected Results: File should be added to archive. Someone reported this on Google+ and I tried it with similar results.
It looks like Kubuntu-specific. I couldn't reproduce the bug neither on Ark master nor on the 15.04 branch.
*** This bug has been marked as a duplicate of bug 340456 ***