I forgot my Firefox Sync Key the other day when I had to sync a new device. I didn’t even know what it was until this happened (note to self – read things more carefully when you install or sign up for something). If you forget or lost your Sync key or you don’t know where to find it, here are the steps I used to get a new Sync key (which I then saved to my passcard in Roboform).
Go to the Firefox menu. Click Tools > Options > Sync. Click to Setup Sync, then follow these steps to get the new Firefox Sync Key )if you already have an existing Firefox Sync account). Here is my step by step guide with screen shots.
After you go to Tools > Options > Sync > Setup Sync you click on Connect if you already have an account.
During the Add Device screen click on: I don't have the device with me.
Enter your account username (which is your email) and your password. Then click on: I have lost my other device.
Now Firefox will create a new Sync Key for you. Keep it, or click Generate to create a new random one. Read the warning! You'll lose existing sync data! Also - WRITE THIS NEW KEY DOWN... so you can use it for your other devices!
Then click the button Change Sync Key. Now Firefox automatically changes your Sync key and starts uploading local data. Wait for it to finish and you'll get a confirmation message.
Your Sync key is now changed! Click Finish and you're all set!
When you generate the new Sync key you should write it down or e-mail it to yourself so you have a copy in the future. Also if you ever get an error after everything is all setup, check out my solution for the unknown Firefox Sync error.