This article is about cause and possible solution for the following error that occurs when attempting to export a VMDK files to a VSphere client:
An internal error occurred in the vSphere Client. Details: Object reference not set to an instance of an object.
A missing line in the .vmdk file can cause this when VSphere tries to get the sparse image of the Datto export.
1. Download the .vmdk file from the datastore, and place the following line in the .vmdk file through a text editor. Be sure to use lower case letters.
ddb.adapterType = lsilogic
If this already exists, make sure it's properly written and that the text is in lowercase.
2. Re-upload the .vmdk to the datastore and attempt to re-attach the disk files.
3. If this issue continues to persist, please contact Datto Technical Support for further assistance.