When i try to install the 0.26 Version, my virus scanner doesn’t allow it and says that TR/Downloader.lkqlp was found.
Somewhere in C:\Users{username}\AppData\Local\SquirrelTemp\VCRedistsInstaller.exe
It also occurs when i scan the fuse_win_0_26_0_7741.exe
Can someone please have a look at that and tell me if it’s dangerous or not?
Most likely your anti-virus scanner is over-active. We’ll take a look at the installer, but chances are low a virus made its way into our build pipeline. 
In addition, it would be good if you could provide more detail on the issue. What virus scanner are you using? Which version of Windows are you running? Where did you download Fuse from (our website or somewhere else?) What’s the MD5 checksum of the installer? (Take a look at https://support.microsoft.com/en-us/kb/889768 to find out how) - we can use that to make sure your installer is the same as we are currently shipping and that it hasn’t been tampered with by a 3rd party.
I use a virus scanner named Avira (http://www.avira.com/) Version 15.0.20.59
Windows 10 Home (with all Updates done)
I downloaded Fuse from the official site (https://www.fusetools.com/downloads)
fuse_win_0_26_0_7741.exe
MD5: 42bdbdf2972aedfc953d59f3502e1be9
SHA-1: c51f003404b646381ecf97b85c1b5c0dff1471c2
That is indeed the correct md5 of the installer executable. I’ll see if we can find out why Avira classifies us as a virus.
To be perfectly clear: there’s no virus or malware in Fuse. The Avira identification is a false positive, and as you can see by this cloud analysis by 57 different virus and malware detection engine, there’s only one identification (which is of questionable quality: it’s a heuristic identification of “generic malware”, which is most likely because the file is an installer that fetches new files from the internet).
TL;DR: no virus. You’re good. Feel free to report the false positive to Avira, as we also have done.
Thanks for taking this serious. I’m very glad i now can upgrade too, without any concerns.
Guess i better should change my virus scanner.
We’ve now also gotten a reply from Avira. They agreed that this is a false positive, and will avoid flagging Fuse as a virus in future versions of Avira. So that should mean less trouble for you in the future. Happy Fusing!
It seems that the problem hasn’t been solved for new Fuse Versions (fuse_win_0_28_1_8199.exe). My Avira also put the installer directly into quarantine after downloading and say it found a TR/Downloader.uasfv trojan. My solution was to deactivate Avira temporary for installing, put of course this doesn’t give you a good feeling.
A Virustotal analysis says that only the avira scanners find something:
https://virustotal.com/de/file/5192257f1a3e53f7df0c13f24b5077456603689de93e8c4b230a5b822080146f/analysis/1478427739/
Johannes: this is not something we at Fuse can influence at all. There is no virus in the Fuse installers, yet Avira keeps misidentifying it. As far as we know, it’s the only out of 50 or so virus scanners that have this false positive. We’ve reported this to Avira and that’s all we can do. Feel free to also report the same to them so perhaps they fix their broken identification engine.