Please find below findings from today remote session with Veeam support:
1.Trend Micro is loaded (services running) into guest VM.
2.When the shadow copy is taken from the host (by Veeam backup), there is a checkpoint file created next to the VM disk; this checkpoint file is then connected to the guest VM and we see it its disk management
3.After the disk is connected, it got to be brought online and mounted so that backup started to take backup from the VM original VHDx file.
4.However, the disk is not brought online, it seems AV prevents disk from being mounted and online, it could be AV is trying to scan the new disk when it tries to come online or trying to scan the boot sector or something. The disk management as a result becomes unresponsive.
5.If we unload Trend Micro (services stopped), the disk created in step 2 above when backup starts is brought online successfully and backup finishes successfully.
6.Per Veeam support, they isolated the issue and found out what can be presented to Trend Micro support.
Maybe there is some options in Trend Micro that you can tune to prevent Trend Micro from accessing the newly created checkpoint (disk) or something..