Broken Attachment Links - shared library

Dear EndNote-Community,

I am having “Broken Attachment Links”-Problems in a shared library. Of all the members of the library, only one person can open the attachments of 253 references that are shown to have “broken attachment links” on all other members computers. Our initial idea was for the person with the working attachements to copy the relevant references (with the attachments) to a new library, delete them from the shared library and then “readd” them in hopes of getting the attachments to work. This worked for arround 2 days, suddenly the status quo has taken over again. The same 253 references are shown to have broken links on everyone’s computers except the one. 

Any ideas what the problem here could be?

With kind regards,