I mistakenly enabled the Pre-release updates (natty-proposed) repository and then upgraded all packages.
How can I undo this?
This page suggests that Apt pinning can be used to downgrade from an entire repository by leveraging the fact that pin priorities higher than 1000 can cause package downgrades.
One solution, then, might be to temporarily increment by 1000 the default priorities of all package files except for those from the
After doing this,
When the downgrade is complete, use Software Sources to disable the Pre-release updates (natty-proposed) repository, then remove the temporary priority increase:
Finally, reboot so that all running programs are their downgraded versions.
Here's a more general way to revert from locally installed packages, proposed and backports packages to the stable+updates channel. While the other answers are correct and work in a similar way, I think this is a more elegant approach.
In synaptic you can disable the repository for proposed and update your sources. Then you'll see than all the packages than have been updated appears as locally installed (since they're not in the repos anymore).
Now you'll have to "downgrade" those packages. Select one by one, and in the upper menu chose:
A menu will appear with the avalliable options. I'd choose the lower version number for each package. If you make a mistake and there's a newer version in the normal repos, it will be solved in a later update.
Whish it helps.
A quick solution would be to use the purge-ppa command pointing to the porposed repository, but don't know if it would work with them, i've only used it to purge external ppa's and downgrade packages to the official ubuntu versions. I won't recomend you to do this in this case, maybe somebody know if it's a safe method...
I cannot find a simpler solution than the following. Yet hoping someone get in with a better answer.
The following script that can execute the downgrade
When running the script, the proposed repo should NOT have been disable yet.
Remember to set the executable bit on both scripts.
A problem with this approach is that all downgraded packages will result as manually installed (also those that were automacally installed).
To be safe, add the
Reverting all packages from natty-proposed is probably not needed: most packages will be updated to the same versions soon through natty-updates anyway.
In case you have a problem with one package, you could revert that one package using the method darent presents (after disabling -proposed), or you can use