After deleting optical drive, it gives below message:
Please advise, how to fix this
For my VM I got IDE Hard disk not SATA like Your screenshoot.
And IDE for me was default for all VM in virtualbox. Physical i have ssd in my laptop. that mean, that this VM IDE or SATA is specify by Virtualbox config. I'm not good in Virtualbox... try some search in "SATA IDE virtualbox" direction.
Sorry, it is the only my guess
I was going to wait to post about this but it will help you out a lot. We have posted a NEW! and improved way to setup EXOS-VM to work with GNS3. It's the easiest way to build EXOS-VM networks that i know of. I didn't come up with it, but I made a guide for it. Try it out and let me know if the guide helps.
Create a new VM
Select Type: Linux and Version: Linux 2.6/3.x/4.x (32 bits)
You don't need much memory to run the VM. I use 256 MB. Adding more does not make much difference.
Don't bother much when creating the disk, as we will delete this later...
Once you have finished, select Settings and then Storage. You will see that the disk was created as SATA. Delete it.
Select the IDE Controller and select Add New Virtual Hard Disk.
Select to create a new disk.
I usually use VMDK format, Dynamic Assignment and no more than 400MB, but you can choose whatever you want.
After that, select the Optical Drive and put the ISO file in it.
Once you've done all this, your VM should look like this and you are ready to start it.
When booting from the ISO file, it will ask to erase the virtual HD and set up a partition scheme. Say Y.
When the process completes, it will ask for a reboot. DON'T REBOOT YET.
Before rebooting, remove the ISO file from the optical drive, or the previous process will repeat again.
Now, you can reboot. The VM should start normally.
You can find more information on configuring the management port in your VM in this post:
Hope this helps.