aptitude - gui - cant find a source to download version package and a fix

Aptitude can save the day! the error happens when we install a package called "x" but version "A-y", well it happens that just at that moment they update and the newer version "A-z" and the apt obviously when you try to download it you won't find it... because of this When trying to reopen aptitude, the following error appears:

Continue to read the solution:

No mater if you use apt, aptitude or dpkg, the error "cant find a source to download version" happens when the mark version to install was upgraded and theres a new one.. but you already performs to install a (now) non-existing version.

The solution:

1 - Search with aptitude the pointed package of the problem.. in this case example the package is "linux-image-4.9.0-19-amd64" so the command must be:

aptitude -V --no-gui search linux-image*

This will permit to check if there are others related.

2 - Then mark as forbiden before fix and remove.. of course you must check if there already some programs using such package, like a service or the OS itselft:

aptitude -V --no-gui forbid-version linux-image-4.9.0-13-amd64

3 - Try to find if there are versions availables (in the case if you cannot remove to then install again like happened with kernels)

apt-get update
aptitude -V --no-gui versions linux-image-4.9.0-19-amd64

This will show this kind of output:

p 4.9.320-2 oldoldstable     500 
p 4.9.320-3 stretch              500

And then you can try to rechoose the right version again, using apt:

apt-get install linux-image-4.9.0-19-amd64=4.9.320-2

4 - Finally if you can (in mayor cases except the libc6 and kernel packages) you can remove to later reinstall again:

dpkg --force-all --purge linux-image-4.9.0-19-amd64

This only affect hardly the aptitude console gui, using only by real hackers!