I thinks its mixed caused i removed my sync account than added it after a long time and firefoxSycn messes it but created duplicated on weird directories

Sync will send information from one system to all others in the sync. There is no 'Master' or 'Primary.' Everything you select is shared.

First, Sync is not a "cloud" service for use with a solitary device and to be turned on & off at will. Sync is intended to "synchronize" Firefox user data across multiple devices and to remain connected to do constant synchronization of that data.

Sync merges all data between the "connected" devices, with certain limitations on Mobile (Smart Phone) devices. Duplication of bookmarks shouldn't occur when used properly.

A new Sync account would be empty - nothing on the Sync server to be merged with the bookmarks on a solitary device. Might be a corrupt Places file on the solitary device, which might account for the "weird directories".

1. Disconnect from the Sync server first, then go to - https://accounts.firefox.com/ - and change your account password to clear your data from the Sync server. DO NOT login to your account just yet.
2. In Help > Troubleshooting Information, all the way down that page, there is a Places Database item; use the Verify Integrity button to "clean" the places.sqlite file.

Hopefully that will solve your duplicated / corrupt bookmarks issue.

Once the verification is done you may login to your Sync account then, but if you are using only one device with Sync there is no real point in doing that. Sync is not a "cloud" to "back up" your Firefox data on one device.

RexaFire said

If i have two different copies one in cloud one desktop which way sync will occur.Will it mix(how) one will be delete and synced

Can it delete bookmarks also

Merge this question and https://support.mozilla.org/en-US/questions/1200897 and https://support.mozilla.org/en-US/questions/1200599