Server upgrade 2025 causes large files not to process

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.