When loading a topology file into GNS3 which worked perfectly before I experienced the following error from time to time:
Last time I faced this error the topology.net file was mixed up due to unknown reason. Let’s see if it’s the same issue again…
When looking on the topology.net file in a text editor the main sections are mixed up in term of numbering regarding the UDP Port numbers (see the red marks):
They should start at port “7200” and increment by 1 for each section.
Order all main sections so that they start again with port 7200 and that the file looks something like this:
After that GNS3 should start up correctly again.