I am using Polaris Office, version 3.0.3245.0 - FV02
(2012 INFRAWARE, Inc www.infraware.co.kr).
on an LG-P940 (PRADA 3 by LG) Mobile Phone, Android v4.0.4.
I was compiling a standard text document and saving regularly as I added new sentences or paragraphs.
After one particular save ( the last one that I did, obviously ) the file extension became .doc.qbk
Subsequently, the text document file will not open, returning the error message : "this file format is not supported".
I have no idea why the file extension became .doc.qbk upon that save alone, without any prior warning message on my screen.
The only difference was that the document had just, upon that editing session, become 2 pages long (15.5KB).