Is it any way to fix this issues with the file uploader in Umbraco forms? - You can't select multiple files from different folders. If you want to upload multiple files, they need to be in the same folder, because you can't add any files towards the already done selection, so they need to be selected in one go. - Every time you click "Choose Files", all pre-existing files get removed. If you click on accident, and then press "Cancel" in the file dialog, again, all files get removed. - There is no way to manage the selected files - i.e. remove a single one from the list.