I am having exactly the same issue as Henrik. Any InDesign files created in either CC 2014 or CS6 are now not opening in CC 2014. Same error code (4). Some files were created months ago, whilst another one was only created yesterday. I cannot open any files. InDesign CC 2014 has the latest updates installed. Any ideas?
Please ignore the above. My problem was fixed with a reboot.
I've had this problem with error 1 and 4 in cc 2015 a number of times. Sometimes a reboot fixes. Usually you can fix it by destroying the preferences file (this seems to be true of many Indesign and Photoshop problems). You must delete it and start again, don't rename a backup copy. This last time it turned out that the preferences pointed to a the backup/recovery folder on a dying drive. Deleting the prefs file and setting the folder to a working drive fixed it.Probably not a common problem, but I thought it worthwhile reporting.