Azure Cosmos Emulator (Windows MSI) error in Microsoft.Azure.Cosmos.StartupEntryPoint.exe

Question

Azure Cosmos Emulator (Windows MSI) error in Microsoft.Azure.Cosmos.StartupEntryPoint.exe

Andriy Svyryd 20 Microsoft Employee

Install the emulator on a fresh Windows Server 2016 Datacenter with .Net Framework 4.8.0 and x64 Visual C++ 2015–2022 Redistributable
Get error on startup in Microsoft.Azure.Cosmos.StartupEntryPoint.exe

Tried the following troubleshooting steps several times:

Restarting
Reinstalling
Resetting data
lodctr /R
Microsoft.Azure.Cosmos.Emulator.exe /GenCert

Andriy Svyryd 20 Reputation points Microsoft Employee

2026-03-11T19:11:27.2733333+00:00

Application: Microsoft.Azure.Cosmos.StartupEntryPoint.exe

Framework Version: v4.0.30319

Description: The process was terminated due to an unhandled exception.

Exception Info: System.Security.Cryptography.CryptographicException

at System.Security.Cryptography.Utils.CreateProvHandle(System.Security.Cryptography.CspParameters, Boolean)

at System.Security.Cryptography.Utils.GetKeyPairHelper(System.Security.Cryptography.CspAlgorithmType, System.Security.Cryptography.CspParameters, Boolean, Int32, System.Security.Cryptography.SafeProvHandle ByRef, System.Security.Cryptography.SafeKeyHandle ByRef)

at System.Security.Cryptography.RSACryptoServiceProvider.GetKeyPair()

at System.Security.Cryptography.RSACryptoServiceProvider..ctor(Int32, System.Security.Cryptography.CspParameters, Boolean)

at System.Security.Cryptography.X509Certificates.X509Certificate2.get_PrivateKey()

at System.Security.Cryptography.X509Certificates.RSACertificateExtensions.GetRSAPrivateKey(System.Security.Cryptography.X509Certificates.X509Certificate2)

at Microsoft.Azure.Cosmos.ServiceFramework.EntryPoint.AclCertificateUtil.SetCertificateAcl(System.Security.Cryptography.X509Certificates.X509Certificate2, System.String, Boolean)

at Microsoft.Azure.Cosmos.ServiceFramework.EntryPoint.AclCertificateUtil.SetCertificateAclByCommonName(System.String, System.String, System.Security.Cryptography.X509Certificates.StoreName, System.Security.Cryptography.X509Certificates.StoreLocation, Boolean, Boolean)

at Microsoft.Azure.Documents.Services.StartupEntryPoint.GatewayServiceSetupCommand.GatewayInit(System.Fabric.CodePackageActivationContext)

at Microsoft.Azure.Documents.Services.StartupEntryPoint.GatewayServiceSetupCommand+c.b__2_1()

at Microsoft.Extensions.CommandLineUtils.CommandLineApplication.Execute(System.String[])

at Microsoft.Azure.Documents.Services.StartupEntryPoint.ServiceStartupEntryPoint.Main(System.String[])
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Andriy Svyryd 20 Reputation points Microsoft Employee

2026-03-11T19:13:36.9133333+00:00

The website doesn't allow me to post any details about the exception for some reason
Andriy Svyryd 20 Reputation points Microsoft Employee

2026-03-20T20:58:18.9966667+00:00

Thanks @Manoj Kumar Boyini .

I understand. My request is that https://learn.microsoft.com/azure/cosmos-db/how-to-develop-emulator?tabs=windows%2Ccsharp&pivots=api-mongodb#prerequisites is updated to remove Windows Server 2016 and avoid wasting time investigating this in the future.
Pilladi Padma Sai Manisha 7,390 Reputation points Microsoft External Staff Moderator

2026-04-03T21:31:18.2366667+00:00

Hi Andriy Svyryd
Just checking in did the solution we provided resolve your issue. Please reply if you have any questions in this matter and we will gladly continue the discussion.

Answer accepted by question author

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Deleted

This comment has been deleted due to a violation of our Code of Conduct. The comment was manually reported or identified through automated detection before action was taken. Please refer to our Code of Conduct for more information.
Andriy Svyryd 20 Reputation points Microsoft Employee

2026-03-11T19:13:36.9133333+00:00

The website doesn't allow me to post any details about the exception for some reason
Andriy Svyryd 20 Reputation points Microsoft Employee

2026-03-20T20:58:18.9966667+00:00

Thanks @Manoj Kumar Boyini .

I understand. My request is that https://learn.microsoft.com/azure/cosmos-db/how-to-develop-emulator?tabs=windows%2Ccsharp&pivots=api-mongodb#prerequisites is updated to remove Windows Server 2016 and avoid wasting time investigating this in the future.
Pilladi Padma Sai Manisha 7,390 Reputation points Microsoft External Staff Moderator

2026-04-03T21:31:18.2366667+00:00

Hi Andriy Svyryd
Just checking in did the solution we provided resolve your issue. Please reply if you have any questions in this matter and we will gladly continue the discussion.

Answer 1

Hi Andriy Svyryd,

The startup failure in Microsoft.Azure.Cosmos.StartupEntryPoint.exe is occurring during certificate and cryptographic initialization. Specifically, the emulator fails while accessing the private key of the self‑signed TLS certificate and setting the required ACLs. This results in the System.Security.Cryptography.CryptographicException you’re seeing and prevents the emulator from starting.

Based on the symptoms and troubleshooting already performed, this is a known class of issue with the Windows MSI version of the Azure Cosmos DB Emulator on Windows Server 2016. The emulator relies on legacy Windows crypto providers and certificate handling that can fail on older or hardened server OS configurations. In these cases, reinstalling, resetting data, regenerating certificates, or repairing counters does not resolve the issue.

The supported and reliable options are:

Run the Cosmos DB Emulator on a newer OS
- Windows Server 2019 or 2022
  - Windows 10 or 11
Use the Cosmos DB Emulator via Docker

This avoids Windows certificate and crypto dependencies entirely
- Recommended for server‑based or CI environments
- Documentation: https://learn.microsoft.com/en-us/azure/cosmos-db/emulator-linux

If upgrading the OS or using Docker is not feasible, the alternative is to use a small Azure-hosted Cosmos DB account (or Free Tier) for development and testing.

Hope this helps, Please let us know if you have any questions and concerns.

Answer 2

Hi Andriy Svyryd,
Thankyou for reaching in microsoft q&A!
The error in Microsoft.Azure.Cosmos.StartupEntryPoint.exe on startup is primarily due to OS compatibility issues.

The Azure Cosmos DB Emulator is not supported on Windows Server 2016, which can cause startup failures even after performing troubleshooting steps like reinstalling, resetting data, or rebuilding performance counters.

The recommended resolution is to upgrade to Windows Server 2022 or later and reinstall the emulator, which has been validated as the effective fix.

This is also reflected in the updated documentation, which clarifies the supported environments and prerequisites for running the emulator.

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Azure Cosmos Emulator (Windows MSI) error in Microsoft.Azure.Cosmos.StartupEntryPoint.exe

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