[opensuse] libre office + thunderbird --> acces denied to user

Hi everyone! Since about 3 days I encounter a strange situation: When I try to open a file from my home/desktop folder with libreoffice the program says, that the file is protected by "unkown user". I can just open it as a working copy or ready-only. Also Thundebird replied, that it is not possible to safe the new e-mails to the disc. Strangly, after a restart, tb worked fine, but libreoffice still has the same problem. Acutally i didn´t make any changes on my system, beside an update…Might this be a security issue? Thanks, Benjamin.