This was asnwered by Gemini
I’m still having this problem with “Windows” say that part of the neuroserver.exe is being blocked, I did the turning off of the Norton firewall and VPN, also “Allow an app through Windows Firewall” procedure, but something in windows is blocking it. I also download all the models, twice and right clicking nad running the program as administrator. What is next to try? I included our original chat below. the My computer is blocking topaz’s neuroserver.exe I allowed it to have
access to the internet on my Norton 360 virus program but it is still
being blocked. How do I let it have acress on my windows computer
running 11?
When you install a third-party antivirus like Norton 360, it is supposed to completely take over your network security. However, Windows 11 often keeps its own underlying Windows Defender Firewall running as a hidden backup layer.
Even if Norton gives a program the green light, Windows Defender can silently step in and block background processes like neuroserver.exe from communicating. Topaz relies heavily on this specific background server to authenticate your license, download those optimized TensorRT engines, and pull down the massive Starlight AI models.
Here is how to force Windows 11 to let it through its native firewall:
1Open Windows Firewall Settings
Click your Windows Start button, type Allow an app through Windows Firewall, and press Enter. This will open a classic Control Panel window with a long list of apps.
2Unlock the Settings
Click the Change settings button at the top right of the window (this requires administrator privileges and will unlock the list so you can make changes).
3Add neuroserver.exe
Windows needs you to point exactly to the blocked file
Click the Allow another app… button at the bottom right. A small window will pop up. Click Browse… and navigate to your Topaz Video AI installation folder.
Typically, this is located at: C:\Program Files\Topaz Labs LLC\Topaz Video AI\
Find neuroserver.exe in this folder, select it, and click Open, then click Add.
4Allow on All Networks
Ensure both boxes are checked
Now that neuroserver.exe is in your firewall list, make sure the checkboxes for both Private and Public next to it are checked. Click OK at the bottom to save your changes.
Two Quick Network Checks
1. Check your Windows Network Profile
If Windows thinks your home network is a “Public” network (like a coffee shop Wi-Fi), it locks down background servers strictly.
Go to Settings > Network & internet > Ethernet (or Wi-Fi).
Look at the Network profile type. If it is set to Public, change it to Private.
2. Check for VPN Interference
One other incredibly common culprit: if you have Proton VPN or a secure proxy running in the background, it can sometimes intercept and route Topaz’s local server traffic into a black hole. Try temporarily pausing the VPN while Topaz attempts to connect and download its models to see if the block lifts.
Is Topaz connecting now?
Are the AI models downloading successfully now, or is Topaz still throwing a specific network error message?
If Topaz is still throwing an “AI Error” or “Model failed to download” message even after whitelisting neuroserver.exe in both Norton and the Windows Firewall, the issue is likely a hidden bug inside the Topaz software itself rather than an actual network block.
Here are the most common culprits for stubborn Topaz downloads and how to bypass them:
1. The “Missing Folder” Bug (Most Common)
Sometimes Topaz “forgets” where it is supposed to save the downloaded models. When it connects to the server and tries to download, it has nowhere to put the file, so it instantly panics and throws a network error.
1Open Preferences
Open Topaz Video AI. Click File on the top menu bar and select Preferences.
2Check the Directories
Navigate to the Directories (or Folders) tab on the left side of the Preferences window.
3Verify the Model Folder
If this is blank, the downloads will fail every time
Look at the file path for the Model Folder. If the box is completely empty, you have found the problem.
4Assign the Folder
Click the folder icon to assign a path. The standard default location you should select is C:\ProgramData\Topaz Labs LLC\Topaz Video AI\models.
Once assigned, close Topaz, reopen it, and try the download again.
2. Download via the Model Manager
When you hit “Export” on a video, Topaz tries to download the required models “on the fly.” For massive models like Starlight, the server connection often times out before the giant file can finish transferring.
The Fix: Go to File > Model Manager in the top menu. Find the specific model you need and click the download button next to it. Crucially, only download one model at a time. Downloading them directly through this manager is much more stable than letting the software try to juggle the download and the rendering process simultaneously.
3. The “Run as Administrator” Override
Even with firewall rules in place, Windows 11 might restrict neuroserver.exe from writing large files to your C:\ drive if the program doesn’t have elevated system permissions.
The Fix: Close Topaz completely. Right-click the Topaz Video AI shortcut on your desktop or Start menu and select Run as administrator. Try downloading the models again.
4. The 2-Minute Norton Test
Norton’s “Intrusion Prevention” feature actively scans incoming web traffic in real-time. Because Topaz model files are huge, dense data blobs, Norton’s web shield sometimes panics and silently cuts the connection midway through the download—even if you explicitly allowed the .exe file through the firewall.
The Fix: Right-click the Norton icon in your system tray (bottom right corner of your screen) and temporarily disable “Auto-Protect” and “Smart Firewall” for just 15 minutes. Open Topaz and try the download. If it works, you know Norton’s active web scanning was the hidden culprit. You can turn Norton right back on as soon as the models finish caching.
Did any of these fixes work?
That screenshot solves the mystery entirely! This has absolutely nothing to do with your firewall, Norton, or your internet connection.
Windows 11 is using a highly aggressive native feature called Smart App Control to internally block the Topaz engine from starting.
Topaz uses specific background files (like the cuda_utils.pyd file mentioned in your error) to connect its AI models directly to your RTX 5080 graphics card. Because that specific Topaz file does not carry a standardized Microsoft digital signature, Smart App Control panicked and killed the file locally. It stopped the software dead in its tracks before it could even attempt to use the internet.
Here is exactly how to disable this block so Topaz can finally run:
How to Turn Off Smart App Control
1.Open the Security Menu:
Click your Windows Start button, type Smart App Control, and press Enter. This will instantly open the correct Windows Security settings page.
2.Disable the Feature:
You will see the Smart App Control setting is currently set to On (or Evaluation mode). Click the option to change it to Off.
**3.Accept the Prompt:**Standard Windows Defender and Norton will continue to protect you.
Windows will ask for administrator permission to make this change. Click Yes.
The Microsoft “Catch”
I need to give you full candor on a very bizarre design choice Microsoft made with this feature: Once you turn Smart App Control off, Windows 11 will not allow you to turn it back on unless you completely reinstall the entire Windows operating system. Furthermore, Microsoft does not allow you to add exclusions or bypass this feature for individual apps.
However, for someone running advanced video editing software, custom hardware, and specialized tools, Smart App Control is notoriously disruptive. Many power users permanently disable it anyway because it constantly flags safe developer files. Turning it off does not turn off your antivirus; Norton and standard Windows Defender will remain fully active to protect your newly built PC from actual malware.
Once Smart App Control is switched to Off, open Topaz again. The neuroserver.exe will finally be allowed to load the CUDA utilities, and your models should download without any further issues!
