Server upgrade 2025 causes large files not to process

Marcel Van Der Merwe 20 Reputation points

When upgrading to sever 2025 we can process small files but fail when we process larger files to outside clients

Moved from Microsoft 365 and Office | Other

  1. Viorel 127K Reputation points

    How can the problem be reproduced?

Sign in to comment

Answer accepted by question author and recommended by moderator

Jason Nguyen Tran 20,115 Reputation points • Independent Advisor

Hi Marcel Van Der Merwe,

This behavior is often related to changes in network stack settings, buffer sizes, or security policies introduced in the new server release.

The first step is to check whether any firewall or proxy settings are limiting file transfer size. Windows Server 2025 enforces stricter defaults for SMB and HTTP transfers, which can cause large file uploads to fail. You should also verify that MTU settings on the network interfaces are consistent with your client environment, as mismatches can block larger packets. Additionally, review IIS or application-level configuration if the transfers are web-based, since request filtering or timeout thresholds may need adjustment.

It is also important to confirm that antivirus or endpoint protection software is not scanning and blocking large files during transfer. Reviewing system and application logs will help identify whether the failure occurs at the transport layer or due to policy restrictions. If necessary, you can temporarily increase buffer sizes or adjust timeout values to confirm whether this resolves the issue.

You can try and let me know the result. Feel free to reply if you need further information.

If you find this answer helpful, please consider clicking Accept Answer so I know your issue has been resolved.

Jason.

  1. Lakshmi Narayana Garikapati 1,330 Reputation points • Microsoft External Staff • Moderator

    Hi Marcel Van Der Merwe,

    I'm Following up to confirm if the earlier responses addressed your query. If not, please share your questions and we’ll assist further

    Thanks,

    Lakshmi.

  2. Lakshmi Narayana Garikapati 1,330 Reputation points • Microsoft External Staff • Moderator

    Hi Marcel Van Der Merwe,

    I'm Following up to confirm if the earlier responses addressed your query. If not, please share your questions and we’ll assist further

    Thanks,

    Lakshmi.

Sign in to comment

1 additional answer

  1. Jason Nguyen Tran 20,115 Reputation points • Independent Advisor

    Hi Marcel Van Der Merwe,

    Just checking in to see if there’s any update on this issue. If the suggestions helped resolve it, I’d appreciate it if you could click accept the answer. And feel free to reply if you need any further assistance. Have a nice day!

    0 comments No comments
    Sign in to comment
Sign in to answer

Your answer