GNS3 Setup: Error opening file for writing, click on Abort to stop installation, Retry to try again, or Ignore to skip this file

GNS3 is a Graphical Network Simulator that allows emulation of complex networks. This program is similar to VMWare or Virtual PC that are used to emulate various operating systems in a virtual environment. These programs allow you to run operating systems in a virtual environment on your computer. GNS3 allows the same type of emulation using Cisco Internetwork Operating Systems (Cisco IOS). See this guide for how to install GNS3 on macOS and how to install GNS3 on Windows.

Here are some other articles I have written on Graphical Network Simulator (GNS3); how to connect GNS3 to the internet on Windows, how to make a router function as a switch in GNS3, and Error: Failed to open a session for the virtual machine GNS3 VM.

The reason for this error is because, some GNS3 files (old installation) were still present at the time of reinstallation as shown below.
- Even when you try to delete these files, you may not be able as the files are currently being utilised by other processes.

Below are some similar errors “You require permission from trusted installer: How to delete or rename files protected by Trusted Installer” as it protects the Os from illegitimate actions such as unauthorized access and changes to these files. For a similar issue, see how to resolve “Error 740: Elevated permissions are required to run DISM“. Also, see Folder Access Denied, you require permission from SYSTEM: Unable to delete old windows folder.

Solution: To fix this issue, simply restart your device or search for the process utilizing these files and kill it.
– I will proceed to restart my device since it is not a production device.
– After restart as you will be able to delete the GNS folder and its associated files as you can see below.

Now, you can continue with your GNS3 re-installation with errors and it will be successful as shown described here “how to install GNS3 on a Windows device“.

I hope you found this blog post helpful. If you have any questions, please let me know in the comment session. I welcome you to follow me on Twitter and Facebook.

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