Hi,
on a FP2 using FPOpenOS
I downloaded - from F-Droid - the app “LibreOffice Viewer” to view a .doc file.
It worked one time. Then it crashes all the time (with the same .doc file).
I opened the .doc file either directly from the inbox (K-9 Mail) or after having saved the document into the Download folder (file opened via Amaze file navigator).
I rebooted the phone with no effect on this.
Any idea ?
Go to Settings > Apps > All and clear cache & data of the app.
If that doesn’t help try a different file. If the crash only happens with that one file it may be corrupted.
It could simply be that LibreOffice viewer is a very buggy app… I use it to view OpenOffice files and it also crashes very often
I use the LibreOffice Viewer for reading .odt and .docx files without problems on my FP2. I have the “Experimental Mode” for editing text disabled because this doesn’t work stable yet.
@mohican you could try to go to settings and make sure the Experimental Mode is not enabled.
I installed TextMaker Free to open DOCs because I read promising things about the now free SoftMaker Apps, but I’ll admit I didn’t stress it yet with complex documents, I just opened some basic DOCs to see whether it works in general (which it did without crashing).
Edit: Ok, curiosity won 
…
TextMaker:
DOC with tables and embedded images 170 KB … no problem.
DOC with tables and embedded images - mail merge 100 pages 14 MB … no problem.
DOC with tables and embedded photos 150 MB … Android requester to cancel App or wait … I waited … a little slow scrolling, if that counts as a problem , no problem otherwise.
The overall structure of the documents was preserved correctly, placing of embedded stuff was minimally off here and there, but nothing much to complain about.
PlanMaker:
XLS with a lot of different tables and VLOOKUPs between them, Hyperlinks and stuff 26 MB … looks and works almost exactly as in Excel … wow 
Presentations:
Don’t have too complicated stuff for that, but
PPT with photos and text 195 MB … no problem.
If in doubt, I would give this set of Apps a try 
.
Eventually I realized that by default F-Droid had installed the 5.0 alpha version of LibreOffice Viewer.
I changed it for the latest 5.2
Bug did not come back on my test file.
-> solved
thanks everybody.