Il proposed repository in Ubuntu it contains unstable packages, still in the testing phase that can cause more or less serious problems until the whole operating system malfunctions.
If you encounter problems after installing these packages, you will need to do them downgrade to a stable version, an operation not so intuitive since it requires adequate knowledge of the Ubuntu update process.
The so-called Upgrade process it is based on specific criteria in the selection of the packages to be installed among the various repositories which consist in assigning priorities to each of them. By appropriately modifying these priorities, it is therefore possible to update the packages not to the latest version available but to the most stable one, here's how:
1. The first step is to disable the proposed repository from Synaptic: start Synaptic go to Settings–> Repository and then in the tab "Updates"And remove the check to"Proposed updates"
2. We then proceed by assigning a very high priority to the packages contained in the repositories: security, updates e backports and assign a negative priority (which prevents the packages from being installed) for the proposed repository.
To do this, create a file called "99-downgrade-proposed"In the folder"/etc/apt/preferences.d/"
$ sudo gedit /etc/apt/preferences.d/99-downgrade-proposed
in the empty file that will open paste the following code:
Package: * Pin: release a = saucy Pin-Priority: 1001 Package: * Pin: release a = saucy-updates Pin-Priority: 1001 Package: * Pin: release a = saucy-security Pin-Priority: 1001 Package: * Pin : release a = saucy-backports Pin-Priority: 1001 Package: * Pin: release a = saucy-proposed Pin-Priority: -1
If you use a version other than Ubuntu Saucy, simply change the word saucy with the name of your version.
3. Now perform a system upgrade and the packages will be automatically updated based on the new priorities set (make sure that the dist-upgrade does not remove important packages for system operation)
$ sudo apt-get update $ sudo apt-get dist-upgrade
4. Finally delete the file created in the 2 point in order to restore the default priorities:
$ sudo rm /etc/apt/preferences.d/99-downgrade-proposed
After downgrading the unstable ubuntu packages due to the proposed repository you will regain complete Ubuntu stability.
Source | Webupd8