Hello,Thanks for taking the time to comment but, and I hope this doesn't sound rude, that is not very helpful. There are a lot of MS Office and other Windows-produced binary files out there. However:The .ods file I was trying to upload was created in LibreOffice on Linux.The issue with corruption of uploaded files has only started happening since I upgraded from 1.6ST to 1.9.15 and the files are stored in the datbase.It is inconceivable that uploading and then downloading binary files should be an issue at all. Many of our customers upload MS Office files, PDFs, images etc. and this has never been an issue with 1.6ST where they are stored on the file system.What I would really like to be able to do is to upgrade my 1.6ST installation leaving the attachments on the file system, i.e. not storing them in the database, and for all subsequent uploaded files to also be stored on the file system. There are two reasons for this.Storing them in the database makes for a very large databaseLeaving them on the file system means that there is no need for manipulation of the source files.Having to use the Storage: plugin to reverse the process of storage in the database seems to me to be a retrograde step. It is also not one I have yet found successful vis-a-vis extracting the existing attachments from the database. I will need to come back to this.Mike