More GNS3 troubleshooting tips here: https://goo.gl/S2fsc8
On MacOSX
THE DMG IS DAMAGED
You need to allow unstrusted applications in your OSX settings.
“GNS3” CAN’T BE OPENED BECAUSE IT IS FROM AN UNIDENTIFIED DEVELOPER.
You need to allow unstrusted applications in your OSX settings.
On Microsoft Windows
UPDATE FOR UNIVERSAL C RUNTIME IN WINDOWS KB2999226
If GNS3 ask you for Update for Universal C Runtime in Windows KB2999226 you need to install it. In theory this is distributed via Windows Update but you can force manual installation:
https://support.microsoft.com/en-us/help/2999226/update-for-universal-c-runtime-in-windows
On Window 7 you need service pack 1.
If you can’t install it you need to investigate why Windows Update is no longer working on your system it could be a virus blocking all updates including security updates.
API-MS-WIN-CRT-RUNTIME-L1-1-0.DLL IS MISSING
Make sure all the Windows update are installed and your computer as reboot. On Window 7 you need service pack 1.
If not working download:
https://download.microsoft.com/download/8/5/e/85edb843-93af-4daa-ad1e-c33dfa95b2ea/vc_redist.x64.exe
Install and reboot
GNS3 STOP WORKING WHEN I OPEN A FILE
If you have Dell Backup and Recovery or Alien Respawn for Alienware, you need to uninstall or upgrade it to version greater than 1.9.2.8. This software conflict with other application using Qt.
On linux
ICON ARE TINY
Solution from fedora wiki:
https://fedoraproject.org/wiki/Common_F25_bugs#Application_issues
Start gns3 in a terminal like this:
QT_SCALE_FACTOR=1 gns3
DYNAMIPS
If you have any issue with Dynamips make sure you are using one of the recommended images listed here
My IOS configuration is not saving
Like a real hardware you need to save the configuration before the device is powered off. You can do that with write memory command.
R1# write memory
My router crash
This could be due to not enough memory.
Dynamips take 100% of my CPU
This could be an invalid IDLE PC value. Edit your router and fix it.
VMWARE
“VMware vmrun tool could not be found” when using VMware workstation player
The free version of VMware doesn’t provide vmrun the command line utility for controlling VMware your need to download it for free from https://www.vmware.com/support/developer/vix-api/
vmrun exit with Unknown error
This error mean VMware has failed due to an internal error. But the VMware tools don’t provide informations when something is wrong on his side.
This could be :
The VM is corrupted
Your VMware installation as expired
VMware ask you something in the GUI
Permissions issue with your VMware installation
It’s very important to run GNS3 and VMware under the same user.
How to troubleshoot:
Start the faulty VM in the GUI
If VM is not working reimport it
If the VM doesn’t work try to import a different VM
If this VM doesn’t work reinstall GNS3
vmrun timeout
This issue is often related to a problem with your antivirus / firewall.
See the official answer from VMware:
https://kb.vmware.com/s/article/2050353
I can’t find VMWare virtual machines in GNS3
The player version of VMware have limitation and if your VM are not in the default directory sometimes GNS3 could not found the VM.
This problem doesn’t occur with the paid version of VMware because a central database is available to third parties applications.
VIRTUALBOX
Invalid VBoxManage executable name VirtualBox.exe
In the GNS3 settings the path for your VBoxManage is incorrect. VirtualBox.exe is the VirtualBox executable, VBoxManage is the application from VirtualBox for controlling VirtualBox it’s two different executables.
Cannot start VM because hardware virtualization (VT-x/AMD-V) is already used by another software like VMware or KVM
Another virtualization software (VMware, Qemu with KVM, Hyper-V…) is already running on your computer and use your CPU hardware virtualization. Only one program can benefits of the hardware acceleration. You need to stop the other program if you want to start VirtualBox.
The following physical network interfaces were not found: vboxnet0
The default VirtualBox interface network interface are not installed on your system. You can fix that in VirtualBox preference or by reinstalling VirtualBox.
QEMU
ASA
Make sure to read the documentation:
https://gns3.com/support/docs/asa-2
And follow the recommendation.
I have trouble with my ASA 8
Asa 8 is not supported use ASAv instead:
