Firmware Upgrade - New Firmware could not be uploaded

Question

Trying to upload SFOS_16.05.6_MR-6 on to our CR35iNG but the manual upload process fails with: 
 New Firmware could not be uploaded. Please refer to online help for possible reasons 
 Have tried FF, IE and Chrome, with the same results. 
 Currently running SFOS 16.05.5 MR-5 and the disk util is: 
 Config: 30% Content: 64% Report: 4% 
 The Content seems quite high, but until now, I've never really paid too much attention to it. 
 Any suggestions?

Jason Shimmin · Accepted Answer

UPDATE and RESOLUTION: 
 After a week with dealing with Sophos support, and several hours of remote support, it was finally discovered that I'd somehow managed to download the firmware for the virtual appliance, rather than for the dedicated firewall. Oops!! 
 In my defence, both the filenames are very similar, and the Sophos support guys didn't even realise either, even though they had tried to upload it themselves. 
 Dedicated firewall firmware filename is: HW-SFOS_16.05.6_MR-6.SF210-266.gpg 
 Virtual firewall firmware filename is: SW-SFOS_16.05.6_MR-6.SFW-266.gpg 
 It's only now that the filenames are obviously different, but I was obviously paying too much attention to the versions numbers in the middle.

PaulMitchener · Answer

Just an FYI that may save someone some time. 
 We had a similar issue on an XG86 trying to upload v18. 
 We downloaded the firmware for a 125, then downloaded the 86 firmware. They were the same file, so windows created the file name with a (1) in the name. The XG rejected it due to the filename being different. Renamed the file to the original filename and it uploaded perfectly.