Exchange Connection Problems

Fix Exchange 2019 eDiscovery PST Export Repeatedly Requesting Credentials

Natalie Taylor Sep 28, 2026 869 views

Question details

The Exchange 2019 eDiscovery PST Export Tool gets stuck in an authentication loop, repeatedly asking for user credentials.

Fix Exchange 2019 eDiscovery PST Export Repeatedly Requesting Credentials

Product: Microsoft Exchange Server 2019
Device & OS: not provided
Scenario: Attempting to export eDiscovery search results to a PST file after recent cumulative updates have been installed.
Observed behavior: The PST Export Tool continuously prompts the user to enter their credentials, even when the account possesses full Exchange administrator permissions and MFA is disabled.

Before you start

Verify whether your Exchange Server 2019 deployment is strictly on-premises or a hybrid environment, and ensure you have administrative privileges to modify Windows Registry settings.

Solution 1Recommended

Apply the Registry Fix for On-Premises Deployments

Add a specific registry key provided in Microsoft's documentation to bypass modern authentication prompts in an on-premises Exchange 2019 environment without MFA.

In strictly on-premises deployments without Multi-Factor Authentication (MFA), cumulative updates can sometimes alter how the PST Export tool handles authentication. Applying the Microsoft-recommended registry edit forces the tool to bypass unnecessary modern authentication requests.

Open Registry Editor

Press the Windows Key + R, type 'regedit' into the Run dialog box, and press Enter to launch the Registry Editor.

Navigate to the Export Tool Key

Follow the path outlined in the official Microsoft Exchange Server 2019 documentation for the eDiscovery PST Export Tool settings.

Add the Authentication DWORD

Create or modify the registry value as described in the Microsoft guidance to disable the modern authentication credential prompts.

Restart the Export Tool

Close the Registry Editor and relaunch the eDiscovery PST Export Tool to verify that the credential loop has been resolved.

Apply the Registry Fix for On-Premises Deployments

On-Premises Fix Verified: This registry modification is confirmed to resolve the issue for on-premises-only deployments that do not utilize MFA.

Solution 2

Review Hybrid Modern Authentication Settings

Check and reconfigure modern authentication settings if your Exchange Server 2019 is part of a hybrid or Microsoft 365 deployment.

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Frequently Asked Questions

Why does the PST Export Tool repeatedly ask for credentials after an update?

Cumulative updates can reset or alter authentication protocols, sometimes causing the tool to default to expecting modern authentication. In an on-premises setup without MFA, this results in an authentication loop.

Does this registry fix apply to Microsoft 365 environments?

No. The registry fix is primarily confirmed for strictly on-premises Exchange Server 2019 deployments. Hybrid or Microsoft 365 environments generally require reviewing modern authentication configurations instead.

Do I need to enable MFA to use the eDiscovery PST Export Tool?

MFA is not strictly required to use the export tool. The tool functions without MFA in on-premises environments, provided the system registry is configured to prevent it from requesting modern authentication credentials.

How do I ensure I have the correct permissions to export eDiscovery searches?

You must be assigned the 'Discovery Management' management role group in Exchange. Standard administrator permissions alone may not be sufficient to perform eDiscovery exports to PST.

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