I've got a fairly new Lenovo A7600-F, which has updated to Android 5 since I purchased it. I'm also fairly new to Android, having gotten my first device (Galaxy S4) five months ago. I wouldn't call myself a power user.
Because I write on my tablet, and on my home computer (Kubuntu 14.04.2 LTS, kept up to date), I searched for a method to directly edit the ODT files from LibreOffice on the tablet, and found AndrOpen Office. Aside from font availability limitations, this has been working pretty well, except for one thing: when I connect the tablet to my computer, I can only access files on the SD card, and then only write to a single folder (LOST.DIR), and files stored there open in AndrOpen Office Writer as read-only, even after formatting the SD card in the tablet. I've tried moving the AndrOpen Office app to SD storage, and that failed, but Android gave no indication (that I've seen) why. Opening a document from internal storage and using "Save As" to put it on the SD card also fails; though I didn't note the exact error message, it said something about "nonexistent object" and "nonexistent file".
I'm able to install other apps directly to SD card when I've selected the SD card as primary write location via Settings. I'm able to copy files to and from the SD card using the File Browser that came pre-installed on the tablet (I'm not sure if this is part of Android or something Lenovo installed; my phone is a Verizon device, and they modify the OS a good bit, making it uncertain to compare built-in apps between phone and tablet). This makes me confident the SD card isn't mounted in read-only mode.
How can I save documents from AndrOpen Office directly to the SD card, or open documents from the SD card in editable form (i.e. to save back to the original file)?