“The operation failed for an undetermined reason” transferring files through vSphere Client (2147256)
Initiating a file upload to datastore, and resulting in the operation failing with an error:
The operation failed for an undetermined reason. Typically this problem occurs due to certificates that the browser does not trust. If you are using self-signed or custom certificates, open the URL below in a new browser tab and accept the certificate, then retry the operation.
To resolve this issue follow the solutions below as per the scenario.
From a client system Web browser, go to the base URL of the vCenter Server system or the vCenter Server Virtual Appliance without appending port numbers or ‘vsphere-client’ extension.
https://vc.gs-01.esgnet.lan/ Enter your vCenter FQDN details on a Web browser
Click the Download trusted root CA certificates link at the bottom of the grey box on the right and download the file.