I have a 4 GB USB stick with almost every portable application available with Liberkey. Though I do not install new applications, the updates have reached to a point that I cannot install an update any more due to disk space problem.

Since I just update the already existing apps, why is the hundreds of megabytes of disk space is lost? Surely an update might introduce some bigger files or new files but still it seems like that updates leave some files back and therefore disk space is exhausted.

Any idea?
Thank you.

libreoffice or openoffice can be huge, check those folders.
you have also to check firefox and opera folders for disk cache size.

and finally, check Liberkey\Apps folder for folders named with a date timestamp at the end, those folders remains due to failed installations, move their contents to the corresponding application folder