Have tried twice to download, via the application currently 12.2.2276 build 12.2.3126.2 for Internet Security; avast! v 12.3.2280 Build 2.3.3154 Both times download was unsuccessful. Each time error occurred about 28% into ais_cmp_sfzone_w7_7cf_7ce.vpx – noted as “unknown error” I took a screen grab w/ Snagit of the final message, too bad I can’t add as attachment. 
So typed it out:
Last encountered error: Unknown error
Total time: 51:18
Download time: 50:36
Downloaded files: 26 (14,605.18 KB)
Server: Download h0356377 AVAST9 Server
Server: http;//h0356377.iavs9x.u.avast.com/iavs9x
http;//h0356377.vpsnitro.u.avast.com/vpsnitro
I have an acer Aspire V3-571w/Windows 10 Home Edition (not switched to Anniversary Update, thank goodness), dual booted w/ Ubuntu 16.04 LTS. I have single drive HDD. The healthy acer partition of 388.63 GB NFTS is 85% free. Current avast! is 12.2.2276 build 12.2.3126.2 Have never had a problem w/ avast! updates in the past.