If I was sending you certain documents - let's say a mortgage deed and a covering letter - I would have both files in a folder and I could see the deed was (let's say) 1mb and the covering letter was 97k So if I sent them to you but you are saying you only have attachments with a size of 1 and 2k we would know the problem is not your ability to open the files, but the fact that either my security, your security or your service provider were stripping out the important documents But if you had file sizes the same as me and you couldn't open them then I would say the problem is definitely on your side So it's about determining where the problem is, to better fix the problem