How to set a file extension on partially transferred files


During a transfer session, the file that is being transferred appears at the destination even if the transfer has not yet finished. The file is considered "partially" transferred because it is still in the process of receiving the data it needs to be the complete file. By default the partially transferred file has the same name as the file on the source, and so is not distinguished for being incomplete.

You can configure files in the process of being transferred to have a file name extension during the transfer, and once the transfer is complete the extension is automatically removed. This way it is easy to tell if a file has not transferred completely, as it will still have the chosen file extension in its name. It is recommended to set a file extension on transferring files, particularly if your file destination is a hot folder. Partially transferred files with an extension are prevented from being downloaded from a hot folder, and this way only complete files are touched.

If you have configured your transferring file to resume at its stoppage point in the event of a transfer interruption, an additional file will appear at the destination. The file is also named after the transferring file and ends in a .aspx extension. It is used to keep track of the file transfer progress at the byte level, and is removed from the destination once the transfer completes.

Note: You should not rely on the presence or absence of the .aspx file at the destination to determine whether a transfer has finished successfully. In some environments the .aspx files may not be able to be deleted, in which case they would remain at the destination along with the completely transferred file. You should instead use the presence or absence of the file extension to indicate incomplete or complete transfers.


1. Partial file name extensions must be set on the destination side of a transfer to take effect, so access the machine(s) which will be used as a transfer destination.

2. You can set the file extension either through the GUI or through the command line.

Via the GUI

Click on the Configuration button on the top-right. Make sure the Global tab is selected to apply the partial extensions to all transfers. You can apply different extensions to particular user groups and even to particular users on the Groups and Users tab in the same way.


Click the File Handling tab. Scroll down to the Partial file name suffix setting and select the Override check box. Enter your desired extension in the text box. The extension can be anything, such as .partial. Click Apply when you’re done and then OK.

Via the command line

Use asconfigurator, which is a tool used to modify the configuration file aspera.conf. Run the following command, replacing partial_extension with your desired partial file extension:

asconfigurator -x "set_node_data;partial_file_suffix,partial_extension"

For example, if we wanted our extension to be .partial, we would use the following:

asconfigurator -x "set_node_data;partial_file_suffix,.partial"
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