. I’m not sure if it is a Serv-U bug or a Firefox bug, but something isn’t playing well with others. https://thwack.solarwinds.com/thread/60471 Based on the info I gleaned from the link I experimented with various combinations of browsing, navigation, entering file names/paths. After manually keying in the full path and file name in the file selection dialog which opens when you browse for a file, the upload worked. Further investigation revealed that any combination which terminates with clicking the Open/Select button on the dialog instead of double clicking the desired file seems to work. The true frustration with all this is that no matter which method you use or which result you wind up with, the only thing displayed in the file name field on the Serv-U dialog is the filename itself without a path. To summarize, if I double click on the highlighted file in the selection dialog below, the filename is populated in the Serv-U dialog as shown in the second image. If I highlight the file and click on the Open button, the filename field is populated as well with no apparent difference. In all the other browsers I’ve tried (and any other application for that matter) either method works as expected. But with Serv-U / Firefox (multiple versions, this was done with 32) the file will fail to upload when you use the doubleclick method with an error stating that the specified file or directory does not exist. Using the highlight / Open button method allows the file upload to work as expected.