Ensure the following prerequisites are met on the client machine:
Install JRE 1.8.
If pop-up blocker is enabled, ensure that the Webtop URL is listed in the Exceptions list of pop-up blocker settings.
Perform the following:
Launch Firefox and log in to Webtop.
When prompted to install the content transfer browser extension, click Install.
When prompted that you are prevented from installing the content transfer browser extension, click Allow and then click Install.
Restart the browser and log in to Webtop.
When prompted to install the native client application, click Save File, click on the saved file prompt, and click OK once the installation is complete.
Restart the browser and log in to Webtop.
You can now perform all the content transfer operations.