Unable to save image to external device

Unable to save image to external device

Hi

We recently purchased OS Deployer 5 (5.0.3,117) but have been encountering issues when saving an image to external USB hard drive.  We have tried two external devices, both 2/3 TB and unused. The external hard drives were recognised when connected to a PC but when we attempt to save an image to the device, OS Deployer doesn't see the device and is unable to save the image.

The external hard drives can then no longer be used as they are not recognized devices regardless of which PC they are connected to.

Can you advise please as we purchased this software on the understanding that it would save us time when configuring and deploying new machines with a standard image?