Avast update 2291, dated 03/30/2017, makes upload of some file types to amazon cloud fail. odt and doc files upload ok. pdf and Quicken backup files fail. Disabling avast web shield allows file uploads to work.
Running Windows 10 Pro 64 bit. Chrome browser. Intel i-7 4 processor, 32 GB RAM memory. Brighthouse (Spectrum) internet (wired). This Avast update automatically downloaded and installed itself and made my backups useless.
Updated April 10, 2017 at noon: problem still not fixed. If I turn on web shield the uploads fail. Turn web shield off and uploads works. Updated April 14 9:40pm- problem still not fixed. Updated April 19, still not fixed.
Updated April 22,2017 - Problem fixed by running avast/repair.
Updated April 23,2017 - Problem started happening again.
Updated May 3,2017 - Problem fixed by Avast update 2294 released today.