Avira in conjunction with autorun.inf

Just delete the autorun.inf file. It'll stop Avira from being dumb.

It is likely due to a previous patch that the autorun functionality is already disabled for removable drives, so rendering the autorun.inf largely pointless.
Sure it can still be useful on your own machines where you are confident enough in the source of removable drives and their contents, but due to lack of confidence in the same for shared/public machaines then it is likely disabled by default to prevent that being one possible entry route for malware.

In the past I've already reported about this topic in the german forum in the article Portableapps. Main reason for the blockade of the Autorun function in your program Avira Free Antivirus is the fact, that your computer should be protected. Especially viruses and Trojans are usually stored in the Autostart, so that they can be start automatically. Accordingly will blocked the Autorun function by Avira, which prevents the execution of such malicious programs. Please read also in the german article under Blockierter Autostart schützt Ihren Computer.

But there exist also the possibility of disabling the protection of the autorun function in your program Avira Free Antivirus.

1. Right click on the icon of your program Avira Free Antivirus in the system tray on the bottom right
2. In the context menu choose the entry "Avira Free Antivirus konfigurieren"
3. Top left activate the "Expertenmodus"
4. Navigate to "Allgemein → Sicherheit" on the left site
5. Uncheck the box next to "Autorun-Funktion blockieren"