Hi wh_linux, Thank you for your question, I am sorry to hear that you cannot find your data. Unfortunately Sync is not a backup, but if you log into the same account on another computer and go to about:accounts to manage the account it should sync all the data to the device. Are any other devices connected to the account?

Thank you for your reply. You noticed me that I have another device connected to the account. But this Monday I has changed my password, and the account is disconnected on this device. I use new password connected to the account this morning and now I got some data, but not all the data. I have more than 30000 rows of history, and now I can only see about 5000 rows of history.

Hey, So yes, unfortunately this is expected behavior for mobile devices. Any history older than 6 month will not show: Bug 985930

The history will sync however some will not be seen because of the mobile device will not download as much history. In the desktop client, only a certain amount of history will show. Please see the thorough explanation rnewman provides in that bug :-) That should help.

Thank you every much!!