Persistent "Validation Failed" error for Android SDK & NDK modules

Hello! I’m experiencing a persistent issue when trying to add Android modules to Unity 6 (6000.1.13f1).

Every download attempt for Android SDK, NDK, and related tools ends with a “Validation Failed” error in Unity Hub. Consequently, the folders remain empty, and the Editor reports: “Selected SDK directory doesn’t exist”.

What I’ve already tried:

  • Complete uninstall and clean reinstall of both Unity and Unity Hub.
  • Switching internet connections and Wi-Fi networks.
  • System reboots.
  • Running Unity Hub as an Administrator.

None of the above worked; the process consistently fails at the validation stage. This also results in multiple “broken” entries of the same Unity version in the Hub. Is there a way to bypass this validation or install the modules manually?



Check the Hub log file to try and understand why it’s failing. Post it here for analysis after a failed install attempt.

Installs may fail for a number of reasons. Largely they are caused by incompatible system settings, a modified/tampered/corrupt system, or software incompatibilities (antivirus is most often to blame as it tends to view developer tools as “nasty”).

Sometimes it’s just a disk being full - consider that the Hub downloads to AppData and then unpacks into TEMP which may be on different drives.

For easiest testing, install the editor without the problematic modules first. Then only try adding the module later so it won’t fail the entire process.

Here is some additional context regarding the issue:

  • System Environment: Running on Windows 10 x64. There is no third-party antivirus installed, so software interference is unlikely.
  • Admin Rights: Running Unity Hub as an Administrator does not resolve the issue. Other modules (e.g., documentation) download and install perfectly fine, which suggests the permissions are not the root cause. The “Validation Failed” error is specific to Android components.
  • Consistency: Android modules used to install and work flawlessly on this same Unity Hub version previously.
  • Log Insights: My Editor.log shows the error Native extension for Android target not found. Additionally, there is a licensing handshake error (ResponseCode: 505, Unsupported protocol version) at startup, which might indicate a compatibility gap between this Hub version and Unity 6.

It seems the validation process for Android SDK is uniquely broken in this setup. I am attaching the full logs for further investigation.


unity hub - last

Hi @MatrixNew

Could we have the Hub logs and we’ll investigate!

Details here: Unity - Manual: Log files reference
In particular the info-log.txt

Thanks for the report!

If you need any additional files, please let me know and I will gladly send them. If a small test or mini experiment is needed for verification, I am also ready to do it. I can also run some PowerShell commands if that helps diagnose the issue. The main thing is to provide the steps in order so I know exactly what needs to be done.

P.S. I already wiped the dust off the monitor — it did not help.

There seem to be a number of failures in the Hub log, I shortened them a bit:

“Failed to fetch eula for android-sdk-ndk-tools, at https://dl.google.com/dl/android/repository/repository2-1.xml
"Could not fetch eula text for Android SDK & NDK Tools, reason: SafeAxiosError: net::ERR_CONNECTION_REFUSED
‘LivePlatformAPI was unable to retrieve releases.’,\n [CombinedError: [Network] request to https://live-platform-api.prd.ld.unity3d.com/graphql failed, reason: connect EACCES
"ApiService: HTTP error! Endpoint: GET https://services.unity.com/api/unity/v3/users/me/context, Body: undefined Status: 401
'Failed to check for updates: Error: net::ERR_NETWORK_ACCESS_DENIED
‘LivePlatformAPI was unable to retrieve releases.’,\n [CombinedError: [Network] request to https://live-platform-api.prd.ld.unity3d.com/graphql failed, reason: connect EACCES
… and others …

Those are the primary failures, and they are network related. Meaning your computer can’t access certain endpoints.

Do you have any “security” software installed? Antivirus + firewall? Or a network setup outside the norm, eg a proxy, a VPN, or a Router that is configured with higher security levels than usual?

"Error checking Visual Studio 2017 installation: Error: vswhere.exe not found - Visual Studio 2017+ not installed or VS Installer not available\n

These repeat for all VS versions, indicating that the VS install of 2017, 2019, 2022, and 2026 either doesn’t exist or is incomplete. This might indicate that VS is entirely absent, which if it is, those errors are expected. But if VS is installed, I’d suggest un- and re-installing (not just “repair install”) all versions. Then install the VS 2022 version only at first, since that’s the version Unity ships with.

But I don’t think these errors are related to the network connectivity issues. More likely they fall in line with potential permission or antivirus issues. Since there are more pointers where the Hub can’t access files on your system:

“First time user check: { hasEditors: true, hasProjects: false, hideGetSetUp: false, hasSeenGetSetUp: false, firstTimeUser: true }”}
‘Failed to download update (promise catch):’, [Error: EPERM: operation not permitted, mkdir ‘C:\Users\MaX\AppData\Local\unityhub-updater\pending’] { errno: -4048, code: ‘EPERM’, syscall: ‘mkdir’, path: ‘C:\\Users\\MaX\\AppData\\Local\\unityhub-updater\\pending’ } ]"}
“Failed to read from C:\Program Files\Unity\Hub\Editor\6000.1.13f1\metadata.hub.json, using fallback release info”}
“Lock contention detected, retrying to acquire lock: C:\Users\MaX\AppData\Roaming\UnityHub\secondaryDownloadLocation.json”}

Hub considers you a “first time user” all the time, indicating it doesn’t persist this status. It also can’t run “mkdir” ie fails to create a folder due to permission issues in that path.

This also points towards Antivirus or misconfigured permissions. Or possibly this:

[ ‘Hub process is running in Administrator mode’ ]

Don’t ever run the Hub as Administrator. And generally: do not launch anything “as Administrator” unless required. Applications will ask you if they need elevated privileges.

Run as admin won’t fix anything, it could only bypass a permission issue that shouldn’t exist in the first place. But running as admin tends to cause more issues further down the line and doesn’t fix the actual problem, merely deferring it at best. If your account is an Administrator account be sure NOT to disable UAC (User Account Control) prompts.

Running the Hub as admin will also launch Unity with admin privileges which is not supported. You’ll get a fairly strong but rather tl;dr; messagebox every time notifying you. It’s highly risky as any script can really do anything to your system. If only by mistake .. ie an accidentally programmed delete C:\*.* due to a malformed path would just wipe entire directories, even drives in an instant, no questions asked.

To clarify once again: I do not have any antivirus installed. In the past, all dependencies installed normally, including Visual Studio, which many people tend to dislike. Visual Studio itself installs without any issues, and the WebGL module also installs fine. The problem only appears with the Android SDK packages.



Are you located in Russia? Could be Roskomnadzor causing those issues. Especially since you use Google’s DNS servers. It might be worthwhile to try the ISP defaults. Otherwise you’ll probably have to use a VPN to use Google’s DNS since Roskomnadzor is known to use deep packet inspection as well as (intermittently or permanently) blocking ranges of IPs.

No, I am not located in Russia. I simply speak several languages, and one of them is Russian. Windows was preinstalled in Russian, so I kept it that way. I am currently located in Spain, in case that information helps with troubleshooting. I also tried changing the DNS servers to Cloudflare and Google and then switching them back to the default settings, but that did not solve the problem.

P.S. I also wiped the dust off the monitor - that did not help either.

Damn, that would have been my next suggestion. :grinning_face_with_smiling_eyes:

I hope staff can provide some ideas next week.

In the meantime you could run the Package Manager troubleshooter script. It’s located in each editor version’s install folder under:

..\Editor\Data\Resources\PackageManager\Diagnostics\RunUnityPackageManagerDiagnostics.bat

You could post the results here.

Hey @MatrixNew

I took a look at the logs and the only issue I see is connectively problems with the Google servers.

{"timestamp":"2026-03-07T07:14:32.744Z","level":"info","moduleName":"Disk Validation Strategy","message":"[ 'Validating source path (https://dl.google.com/android/repository/build-tools_r34-windows.zip) availability...' ]"}
{"timestamp":"2026-03-07T07:14:32.746Z","level":"error","moduleName":"Disk Validation Strategy","message":"[ \"Error occured in 'Source Availablity Check'. Error: connect ECONNREFUSED 127.0.0.1:443\" ]"}

Do you have a VPN? It looks like the google urls are being pointed to your localhost (see the 127.0.0.1:443 above)

I do not have a VPN installed, since I simply do not need one. I live in Spain, where the internet is fast and, most importantly for me, unrestricted. So I do not understand why this issue is happening. Perhaps you could provide the names of the files or processes that connect to these services. I have a firewall installed, and it is possible that it may have blocked a file or service related to the Android SDK or similar components. If you send me a list of those files or processes, I can check everything on my side and try to determine whether that is the cause. I will review it and definitely get back to you…

@MatrixNew

This is one of the urls the Hub is failing to resolve on your machine: https://dl.google.com/android/repository/build-tools_r34-windows.zip


Yeah, man, you were right. The firewall had actually blocked dl.google.com specifically because it considered the number of requests from that address suspiciously high. So the conclusion is simple: AI should not always be trusted, and if it is built into your firewall, it is even more important to double-check everything manually.