[Reference] Common iTunes error codes and solutions. Surprisingly, I haven't seen a thread like this yet, so why not make one to cut down on the repetitive questions? Lets Get Started. Most info is from Apple, while some jailbreak wise info is included, as well as info Apple doesn't say about. iTunes Error Codes. Error 3194 - This Device is not eligible for the requested build. This is the most common error I have seen people ask about. This error will occur when you try to downgrade to a lower firmware. iTunes does not allow this, but as you know, Saurik has his SHSH server to allow SHSH backup for restoring to an earlier firmware at a later point in life. If your SHSH's are backed up, the easiest way to restore is to download and run TinyTSS, a restore server for downgrading and bypassing Apple's regular signature check. Alternately, you can add 126.96.36.199 gs.apple.com to the hosts file on your computer [ you will need to remove it if you're going to update to a beta or such. ] Error 2 Your firewall or third party security software may be preventing iTunes from completing its task. Add an exception or temporarily disable it. Error 6 Your best bet is to try a different computer or disable some software if you don't understand what is being said. Error -4 Check your firewall settings, or try again later. Error 9 This is fairly common for some. This happens most likely when you unplug your iDevice during a restore. If you didn't do it, Windows [Well OS X wouldn'tdo that Please Register or Log in to view images ] may have randomly disabled the the USB port [ it could happen if the driver malfunctions out of nowhere. ]. Try to restore again, try changing USB ports, try restarting your computer, or try a different computer. Error 13 and 14 Windows Users: This error may also occur if you try to update to a beta firmware that's restricted to Mac Users only. Error 18 (or -18) If not, uninstall iTunes and remove your iTunes Library.itdb file. then Reinstall iTunes. Error -19 Error 1603 iTunes failed to place the device in Recovery Mode. Turn off the device. Hold the Home button and plug your device into the computer and try again [ you will lose all unsaved data. ] Error 1604 I would have explained this one but Apple does it better.. in some cases. [This being one of them.] Alternately, this may occur when trying to restore to a custom firmware without SHSH's. [ MC Devices only ] MORE ERRORS ARE COMING ! I Have a fear that my laptop will have a random BSOD so I'll post these up, and edit in the rest when my laptop is safe or when I get to the MacBook.