This thread is for people having this issue, which mainly occurs with PDF documents. I hope that if we direct everyone having this problem to this one thread, and it becomes more and more common, maybe we can get some answers on this instead of sporadic threads with only a few responses each.
Before I go on, I wanted to point out and please ask people NOT to recommend different programs to open PDF files. This issue is NOT about the program used to open the PDF files, as this is definitely a problem with either the email client on the Android or the way the Android retrieves messages from the server. This is an issue no matter if you are using Documents to Go (full), Beam Reader, you name it.
Here is a description of the issue you may or may not be having:
You go to open a PDF document (sometimes other documents as well, not just PDF, but PDF is definitely the most prevalent) and the email client (purportedly a problem with both K9 and the stock email application) and it says "Fetching Document" followed (after a long time) by ""This attachment cannot be displayed."
Here is how you know if your issue is the one being discussed in the thread or something entirely different:
If you check the same email on your home computer, save the file to the desktop, and re-email it to yourself in a new email and it works, you have the issue. Otherwise, it might be something as simple as installing a different document reader.
The issue, as far as I have found in hours of trying to research this via Google and other Android websites, is that if a file is automatically generated (for me, I only notice this problem from my travel agency that auto generates my itinerary in PDF format), and/or has the file name contained within << *.pdf >>, this causes the problems. There could be more problems, or I could not be entirely understanding what is causing the problem, but thus far, this is what I have found.
The only solutions that I have found thus far are not really what I would call solutions to the problems, but rather, bandaids.
1) If you are getting this problem because it is a travel agency auto generating like in my case (probably rare, but worth mentioning)...downloading the program TripIt and forwarding your PDF flight itinerary to them works perfect.
2) It somewhat defeats the purpose of having a phone to check PDF documents, but if you save it to your computer and re-email it to yourself, you can 99% of the time now view the PDF document for some reason.
3) At least one user has reported that using K9 instead of the default application will solve the problem.
Why are so many capabilities left off this phone? - Android Forums
Below are some search terms that have nothing to do with the thread, but I'd like people to be able to easily find this thread...
motorola droid android documents to go beam reader cannot can not open pdf documents can't cant This attachment cannot be displayed fetching