Using QFtp together with the QProgressDialog will randomly lose some data from the end of a file during a get operation.
This can be reproduced with the ftp example in Qt, but I have also attached an example application that downloads the same file 50 times with some debug output to make it simpler to test this.
I have tested this against Nokias Qt ftp site and it seems like I only have this issue with some files. The example is setup to download one such file that has this issue.

It turns out that the problem happens when I use a QProgressDialog and I connect in to the setValue slot of the progress dialog. If I comment out that connection then all files are transferred ok. If the bad line is left in the code, then probably 80% of the 50 files transfer ok, but the others are slightly short by varying amounts, typically anything up to 20k is missing.