Files downloaded from other locations are not marked as “executable” since they did not get installed via a trusted software repository. Because of this, attempting to open downloaded files that are untrusted software will fail. The primary reason for blocking this software is to help unsuspecting users avoid malware (i.e. malicious software like trojan horses, worms, and viruses).
I encountered this issue after I upgraded to Ubuntu 10.4 Lucid Lynx while trying to run Reinvigorate’s Snoop app which is an executable file (.exe). I had been running this file without any problems prior to the upgrade with previous versions of Ubuntu. When I tried to run the .exe file, it gave me this error message:
I know some of you have encountered or are experiencing the same problem but don’t know what to do or how to solve it, so I’m sharing with you today how you can install untrusted software on Ubuntu. The solution is very simple and only takes a few seconds to do it.
1. Right-click on the file that you want to run/install.
2. Click on Properties.
3. Click on Permissions tab.
4. Check the box for “Allow executing the file as a program“.
5. Click Close.
That’s it, simple as that. Now you can run/install the “untrusted” software without any problems.
NOTE: Make sure that the “untrusted” software that you’re trying to run/install is not malware. This method can’t be applied to run/install .exe files on CDs because by default, CDs are mounted with all files set to -x, meaning they are not executable and because executable permissions on a CD cannot be changed.