So I download some software from Sourceforge and my AV (ESET) gos mad and warns me about some variant of Win32/InstallCore.PO. I also noticed the file icon from Sourceforge is "SF".
Downloaded the software from the site itself and nothing, no warnings and the icon is the standard windows application icon.
Uploaded both files to VirusTotal and here is the results
There was a topic about it before, lost in the multitude of posts after it though. SF including adware has been going on for sometime now. At least your antivirus warned you!
An easy solution is to only download archived versions (7z, ZIP, RAR) of software from SF (found in the Files link on their pages) and completely avoid the installers (EXE, MSI).
Looks like times are getting tough if most of the portals are including adware.
SF was bought though, then came the adware. The reason some of your installations didn't have is the refusal of those developers to use it, and/or SF hasn't got around to repackaging that setup file being that they have so many to go through.
I can't remember what developer it was (some popular program) that left SF over the adware bundling, damn can't remember the name of it but it was on allot of tech related sites as "big news."