# Arsim fails to boot **URL:** \ **Category:** B&R Software & Runtime\ **Tags:** automation-studio\ **Created:** [December 19, 2023, 4:47pm UTC](https://community.br-automation.com/t/arsim-fails-to-boot/1638 "2023-12-19T16:47:11Z")\ **Posts on this page:** 1\ **Showing post:** 19
**Author:** ![Jim\_Sculley](https://avatars.discourse-cdn.com/v4/letter/j/FF8800/32.png) [@Jim\_Sculley](https://community.br-automation.com/u/Jim_Sculley)\ **Post date:** [December 21, 2023, 4:58pm UTC](https://community.br-automation.com/t/arsim-fails-to-boot/1638/19 "2023-12-21T16:58:57Z")
OK. It looks like the root cause was Windows Defender Firewall. I haven’t absolutely verified this, but I’m confident. On the new VM, when ar000.exe starts, Defender pops up a dialog to allow ar000.exe to open ports. On all other machines I’ve tried, the dialog never appears. I’ve seen this dialog pop up in many videos I watched while troubleshooting this problem, but I always assumed that I didn’t see it because the firewall is listed as off for all networks: ![image](https://europe1.discourse-cdn.com/brcommunity/original/1X/9b444e4af810210ea4fe65085046d703043300d9.png) But, apparently sometimes [**OFF isn’t really off**](https://windowsreport.com/firewall-disabled-still-blocking/). I’ll have IT check into it and if that doesn’t fix things, I’ll report back. Otherwise, I would consider this solved. --- _[View the full topic](https://community.br-automation.com/t/arsim-fails-to-boot/1638)._