Windows 10 reached EOS (end of support) on October 14, 2025. If you are on Windows 10, see this article.

Avatar for Username

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More
Lolu chungechunge lwabekwa kunqolobane. Uyacelwa ubuze umbuzo omusha uma udinga usizo.
Okugcinwe kunqolobane

Thunderbird 128.10.1 ESR shows blank when opening .eml from NAS (128.5.2 ESR works fine)

I-Thunderbird Connectivity
Wayne Mery replied 1 unyaka odlule
Ronny Chen
Ronny Chen

In Thunderbird 128.10.1 ESR, opening a .eml file directly from a NAS (SMB path) results in a blank message window. However, if I copy the same file to the local desktop and open it, the content displays correctly.

I tested Thunderbird 128.5.2 ESR, and it can open the same .eml file from NAS without any issue, so this seems to be a regression in 128.10.1.

I tried modifying the following config values with no effect:

security.sandbox.content.level = 0

security.fileuri.strict_origin_policy = false

Is this a new security restriction or a bug? Any workaround or fix available? Thanks!

In Thunderbird 128.10.1 ESR, opening a .eml file directly from a NAS (SMB path) results in a blank message window. However, if I copy the same file to the local desktop and open it, the content displays correctly. I tested Thunderbird 128.5.2 ESR, and it can open the same .eml file from NAS without any issue, so this seems to be a regression in 128.10.1. I tried modifying the following config values with no effect: security.sandbox.content.level = 0 security.fileuri.strict_origin_policy = false Is this a new security restriction or a bug? Any workaround or fix available? Thanks!
Ama-screenshot ananyekiwe

All Replies (3)

Wayne Mery
Wayne Mery
  • Umongameli
  • Abanegalelo Abayi-10 Abaphambili

Your problem is https://bugzilla.mozilla.org/show_bug.cgi?id=1966256. The workaround is to change the UNC path you are using somewhere in Thunderbird to be a mapped drive.

Please confirm.

Ronny Chen
Ronny Chen Umnikazi wombuzo

韋恩·梅里 said
您的問題是 https://bugzilla.mozilla.org/show_bug.cgi?id=1966256。解決方法是將 Thunderbird 中某處使用的 UNC 路徑變更為映射磁碟機。請確認。

Thank you, Wayne.

Yes, that is indeed the issue. I appreciate your confirmation and the suggested workaround.

However, due to company policy and workflow requirements, we rely on opening .eml files directly from UNC paths and would prefer not to switch to mapped drives.

I hope this issue can be fully resolved in a future release so that Thunderbird continues to support UNC paths as in previous versions.

Thanks again for your help!

Wayne Mery
Wayne Mery
  • Umongameli
  • Abanegalelo Abayi-10 Abaphambili

A fix in the beta version is available for your testing at https://bugzilla.mozilla.org/show_bug.cgi?id=1966256#c47 If you are able to test, please post your results here.