The Err 4 message may appear on your Play the first time you attempt to sync the Play with a Windows computer.
In order to clear the err:4 message you will need to pair/connect the Play with any Android or iOS device running at least Android 4.3 or iOS 7.1 (iPhone 4 excluded) respectively. You'll need to download the Striiv Activity Tracker app to the device and create an account to pair the Play with the app. Alternatively, you can sync the Play with any Apple computer to clear the err:4 message using the sync software found here: http://www.striiv.com/playdownload/?platform=mac
After you download the software, run the download. Plug in your Play. You will need to toggle between screens using the toggle button to the right of the Play's screen the first time you sync to be sure it stays on for the system to recognize it.
In the past, we did have a fix which could be applied on our end to clear the err:4 message, but this has since stopped working. Pairing the Play with an Android/iOS device or Mac computer at least once will clear the err:4 message and allow you to freely link the Play with any Windows computer without issue.
If you don't have access to an Apple computer or Android/iOS mobile device, email us at email@example.com for further assistance.