In some cases the mouse is not visible in a virtual machine console opened from VMware vCenter 6.5. In this case the VM is booted into the System Recovery Environment (SRE) used for system recovery. Though present, the mouse pointer is displayed so small that it cannot be used to click through the recovery screens.
To work around the issue, identify the ESX host of the virtual machine and open a remote console from this host. To do so, log onto the ESX host through its web interface, click on the SRE booted virtual machine by name under the Virtual Machines navigator table, then click the Console drop down box in the right hand pane. Click to download the VMRC and install it if it has not already been installed on your workstation. Then, click the Console drop down menu 'Launch remote console'.