For general instructions on how to register and unlock iExplorer, please see How do I register iExplorer?.
If your 25 digit registration code is coming up as Invalid in iExplorer, you'll first want to make sure you are definitely entering it into iExplorer and using the major version of iExplorer that you purchased since an older iExplorer 3 license code will be rejected as Invalid if you try use it in our recently released and all new iExplorer 4 app which is a major version upgrade that requires a new license code and adds iOS 10 and macOS Sierra support and includes several UI improvements and performance upgrades. iExplorer 4 needs to be downloaded as a separate, new app since it's considered a new product. To find out which major version of iExplorer you are using, the quickest way is to look at the color of iExplorer's app icon. iExplorer 3's icon has a blue background, and iExplorer 4 has a white background. If you do have a registration code for major version 3 and wish to keep using it but have already installed iExplorer 4, you can download and reinstall iExplorer 3 from the links below:
Download iExplorer 3 for Windows
Download Explorer 3 for Mac
Since iExplorer 4 is the most current major version we offer, the Download buttons for iExplorer on our website will be for installing major version 4, but our Downloads page still has iExplorer 3 download links which is necessary for Windows XP or Vista users and Mac OS 10.7 or 10.8 users since those operating systems don't meet the minimum system requirements for iExplorer 4 and even iOS 10. The Downloads page also has a link specifically for Mac OS 10.6 users that Apple only supports up to iOS 8 (see the 10.6 section below for more info).
If you own an iExplorer 3 license and would like to upgrade to iExplorer 4 at a discounted price, you can go to the link below and enter the same email you used when purchasing iExplorer 3, and your discount will be determined by how long ago you purchased major version 3:
If you still can't register iExplorer using the registration code that corresponds to the major version of iExplorer that you own and are using, make sure you are entering your iExplorer code exactly by using copy & paste to avoid any typos such as mistaking a 5 for an S or a 2 for a Z, etc. If it still won't accept your registration code, try completely closing iExplorer, reopen it, and then copy & paste your code into iExplorer again.
Mac OS 10.6 Snow Leopard
If you have a Mac still running 10.6 Snow Leopard then you'll need to install a more recent version of iExplorer 3 that is specifically built for 10.6 users that will let you register it with our new iExplorer 4 codes. You won't be able to get this update within the app though FYI. You must download it from our website, but to make it easier, here's a download link for version 18.104.22.168 that will automatically start the download for you:
(choose to Replace the iExplorer in your Apps folder when prompted)
Apple officially stopped supporting Mac OS 10.6 in early 2014 and then cut iOS compatibility for it starting with iOS 9 in 2015 when they didn't release an iTunes compatible version to connect and sync with iOS 9 and then iOS 10 too. This is most likely due to the fact that 10.6 is now over 7 years old and six OS versions back from their newest MacOS Sierra (10.12), so we also stopped releasing iExplorer updates for 10.6 beginning with iExplorer 3.9 because 10.6 uses some older frameworks that really limit our development options and the enhancements we can add to iExplorer.