Microsoft 365 のサービス正常性（TM445479）にて、Microsoft Teams デスクトップ クライアントのチャネルからファイル名に UTF – 8 でエンコードされた文字が含まれたファイルを DL（ダウンロード）すると、ファイル名が文字化けすることがあるアドバイザリが発生していました。

“TM445479” のサマリー

目次

Users may see distorted file names when downloading files that have UTF-8 encoded characters in the name – TM445479

サービス：Microsoft Teams

状態：Service restored

ユーザーへの影響：Users may see distorted file names when downloading files with UTF-8 encoded characters in the name.

Microsoft 365 のサービス正常性（TM445479）にて、Microsoft Teams デスクトップ クライアントのチャネルからファイル名に UTF – 8 でエンコードされた文字が含まれたファイルを DL（ダウンロード）すると、ファイル名が文字化けすることがあるアドバイザリが発生していました。

なお、この問題は Microsoft Teams デスクトップ クライアント（Windows／Mac）のチャットや Microsoft Teams ブラウザー版から DL（ダウンロード）を行うことで回避が可能です。

加えて、Microsoft Teams デスクトップ クライアント（Windows／Mac）の上部にある [SharePoint で開く] から、SharePoint Online のドキュメント ライブラリへアクセスして、該当ファイルを DL（ダウンロード）することでも回避できます。

この問題は、ファイル名のエンコードを改善するための最近のアップデート内にコードの問題が含まれていたことから、Microsoft Teams デスクトップ クライアントのチャネル経由で DL（ダウンロード）すると、ファイル名が文字化けして生成される事象になります。

現在は、修正プログラムの展開後、広範なモニタリングと一部の影響を受けていたユーザーへの確認し、根本的な問題が完全に改善されたことを確認しました。

今後は、開発およびテスト サイクルにおいて同様の問題を特定し、将来的に同様の影響を回避できるようにサービスのアップデート手順を見直します。

この問題は、Microsoft Teams デスクトップ クライアントのチャネルから、ファイル名に UTF – 8 でエンコードされた文字が含まれたファイルを DL（ダウンロード）する、すべてのユーザーに影響する可能性がある事象になります。

November 30, 2022 3:49 AM – Service restored

• ・Title : Users may see distorted file names when downloading files that have UTF-8 encoded characters in the name
• ・User Impact : Users may have seen distorted file names when downloading files with UTF-8 encoded characters in the name.
• ・More info : Impact only occurred when the files had UTF-8 encoded characters in the name and were downloaded from channels in the Microsoft Teams desktop client.
• Downloading files elsewhere in the Microsoft Teams desktop and Mac clients (such as from chats) and from the Microsoft Teams web app showed the file names correctly.
• While we were focused on remediation, users could have used the “Open in SharePoint” option at the top of the Microsoft Teams desktop and Mac clients, which would have allowed the files to be downloaded with the correct names from SharePoint Online.
• ・Final status : We’ve verified after extensive monitoring and confirming with some affected users, that the fix has fully resolved the underlying issue and impact has been remediated.
• ・Scope of impact : This issue may have affected any user who downloaded files with UTF-8 encoded characters in the name from channels in the Microsoft Teams desktop clients.
• ・Start time : Tuesday, July 26, 2022, 9:00 PM (12:00 PM UTC)
• ・End time : Friday, November 18, 2022, 4:30 AM (11/17/2022, 7:30 PM UTC)
• ・Root cause : A recent update meant to improve the encoding for file names contained a code issue which caused files with UTF-8 encoded characters to produce distorted file names upon download via channels in the Microsoft Teams desktop client.
• ・Next steps : – We’re reviewing our service update procedures so we can better identify similar issues during our development and testing cycles and avoid comparable impact in the future.
• This is the final update for the event.

November 29, 2022 6:48 PM – Service restored

• ・Title : Users may see distorted file names when downloading files that have UTF-8 encoded characters in the name
• ・User Impact : Users may see distorted file names when downloading files with UTF-8 encoded characters in the name.
• ・More info : The impact only occurs when the files have UTF-8 encoded characters in the name and are downloaded from channels in the Microsoft Teams desktop client.
• Downloading files elsewhere in the Microsoft Teams desktop and Mac clients (such as from chats) and from the Microsoft Teams web app shows the file names correctly.
• While we’re focused on remediation, users can use the “Open in SharePoint” option at the top of the Microsoft Teams desktop and Mac clients, which will allow the files to be downloaded with the correct names from SharePoint Online.
• ・Current status : The fix has been fully saturated to all impacted environments and we are now carrying out extensive monitoring and checks to ensure the fix fully resolves impact.
• ・Scope of impact : This issue may affect any users who download files with UTF-8 encoded characters in the name from channels in the Microsoft Teams desktop clients.
• ・Root cause : A recent update meant to improve the encoding for file names contains a code issue which is causing files with UTF-8 encoded characters to produce distorted file names upon download via channels in the Microsoft Teams desktop client.
• ・Next update by : Wednesday, November 30, 2022, 4:00 AM (11/29/2022, 7:00 PM UTC)

November 17, 2022 6:39 PM – Service restored

• ・Title : Users may see distorted file names when downloading files that have UTF-8 encoded characters in the name
• ・User Impact : Users may see distorted file names when downloading files with UTF-8 encoded characters in the name.
• ・More info : The impact only occurs when the files have UTF-8 encoded characters in the name and are downloaded from channels in the Microsoft Teams desktop client.
• Downloading files elsewhere in the Microsoft Teams desktop and Mac clients (such as from chats) and from the Microsoft Teams web app shows the file names correctly.
• While we’re focused on remediation, users can use the “Open in SharePoint” option at the top of the Microsoft Teams desktop and Mac clients, which will allow the files to be downloaded with the correct names from SharePoint Online.
• ・Current status : We’ve deployed the fix to the impacted environment which we anticipate its completion by the next scheduled update.
• ・Scope of impact : This issue may affect any users who download files with UTF-8 encoded characters in the name from channels in the Microsoft Teams desktop clients.
• ・Root cause : A recent update meant to improve the encoding for file names contains a code issue which is causing files with UTF-8 encoded characters to produce distorted file names upon download via channels in the Microsoft Teams desktop client.
• ・Next update by : Tuesday, November 29, 2022, 7:00 PM (10:00 AM UTC)

October 18, 2022 6:47 PM – Service restored

• ・Title : Users may see distorted file names when downloading files that have UTF-8 encoded characters in the name
• ・User Impact : Users may see distorted file names when downloading files with UTF-8 encoded characters in the name.
• ・More info : The impact only occurs when the files have UTF-8 encoded characters in the name and are downloaded from channels in the Microsoft Teams desktop client.
• Downloading files elsewhere in the Microsoft Teams desktop and Mac clients (such as from chats) and from the Microsoft Teams web app shows the file names correctly.
• While we’re focused on remediation, users can use the “Open in SharePoint” option at the top of the Microsoft Teams desktop and Mac clients, which will allow the files to be downloaded with the correct names from SharePoint Online.
• ・Current status : We’ve completed our validation, and we’re now preparing the fix prior to its deployment.
• We anticipate its completion by the next scheduled update.
• ・Scope of impact : This issue may affect any users who download files with UTF-8 encoded characters in the name from channels in the Microsoft Teams desktop clients.
• ・Root cause : A recent update meant to improve the encoding for file names contains a code issue which is causing files with UTF-8 encoded characters to produce distorted file names upon download via channels in the Microsoft Teams desktop client.
• ・Next update by : Tuesday, November 29, 2022, 7:00 PM (10:00 AM UTC)

October 18, 2022 4:50 AM – Service restored

• ・Title : Users may see distorted file names when downloading files that have UTF-8 encoded characters in the name
• ・User Impact : Users may see distorted file names when downloading files with UTF-8 encoded characters in the name.
• ・More info : The impact only occurs when the files have UTF-8 encoded characters in the name and are downloaded from channels in the Microsoft Teams desktop client.
• Downloading files elsewhere in the Microsoft Teams desktop and Mac clients (such as from chats) and from the Microsoft Teams web app shows the file names correctly.
• While we’re focused on remediation, users can use the “Open in SharePoint” option at the top of the Microsoft Teams desktop and Mac clients, which will allow the files to be downloaded with the correct names from SharePoint Online.
• ・Current status : We’re continuing our evaluation and validation of the reverting actions and expect to have a remediation timeline by the next scheduled update.
• ・Scope of impact : This issue may affect any users who download files with UTF-8 encoded characters in the name from channels in the Microsoft Teams desktop clients.
• ・Root cause: A recent update meant to improve the encoding for file names contains a code issue which is causing files with UTF-8 encoded characters to produce distorted file names upon download via channels in the Microsoft Teams desktop client.
• ・Next update by: Tuesday, October 18, 2022, 7:00 PM (10:00 AM UTC)

October 14, 2022 4:57 AM – Service restored

• ・Title : Users may see distorted file names when downloading files that have UTF-8 encoded characters in the name
• ・User Impact : Users may see distorted file names when downloading files with UTF-8 encoded characters in the name.
• ・More info : The impact only occurs when the files have UTF-8 encoded characters in the name and are downloaded from channels in the Microsoft Teams desktop client.
• Downloading files elsewhere in the Microsoft Teams desktop and Mac clients (such as from chats) and from the Microsoft Teams web app shows the file names correctly.
• While we’re focused on remediation, users can use the “Open in SharePoint” option at the top of the Microsoft Teams desktop and Mac clients, which will allow the files to be downloaded with the correct names from SharePoint Online.
• ・Current status : Our investigation has determined that a recent update meant to improve the encoding for file names contains a code issue which is causing files with UTF-8 encoded characters to produce distorted file names upon download via the affected avenues.
• We’re in the initial stages of reverting the offending change and will validate the efficacy of this remediation as we continue the process of reverting the offending change more broadly.
• ・Scope of impact : This issue may affect any users who download files with UTF-8 encoded characters in the name from channels in the Microsoft Teams desktop clients.
• ・Root cause : A recent update meant to improve the encoding for file names contains a code issue which is causing files with UTF-8 encoded characters to produce distorted file names upon download via channels in the Microsoft Teams desktop client.
• ・Next update by : Tuesday, October 18, 2022, 6:00 AM (10/17/2022, 9:00 PM UTC)

October 13, 2022 10:18 PM – Service restored

• ・Title : Users may see distorted file names when downloading files that have UTF-8 encoded characters in the name
• ・User Impact : Users may see distorted file names when downloading files with UTF-8 encoded characters in the name.
• ・More info : The impact only occurs when the files have UTF-8 encoded characters in the name and are downloaded from channels in the Microsoft Teams desktop clients.
• Downloading files elsewhere in the Microsoft Teams desktop and Mac clients (such as from chats) and from the Microsoft Teams web app shows the file names correctly.
• While we’re focused on remediation, users can use the “Open in SharePoint” option at the top of the Microsoft Teams desktop and Mac clients, which will allow the files to be downloaded with the correct names from SharePoint Online.
• ・Current status : Our investigation in to the root cause has so far been inconclusive.
• We’re continuing to analyze Microsoft Teams diagnostic logs to assist in identifying the source of the problem, in order to develop a remediation plan.
• ・Scope of impact : This issue may affect any users who download files with UTF-8 encoded characters in the name from channels in the Microsoft Teams desktop clients.
• ・Next update by: Friday, October 14, 2022, 6:00 AM (10/13/2022, 9:00 PM UTC)

October 13, 2022 4:34 PM – Service restored

• ・Title : Users may see distorted file names when downloading files that have UTF-8 encoded characters in the name
• ・User Impact : Users may see distorted file names when downloading files with UTF-8 encoded characters in the name.
• ・More info : The impact only occurs when the files have UTF-8 encoded characters in the name, and are downloaded from channels in the Microsoft Teams desktop clients.
• Downloading files elsewhere in the Microsoft Teams desktop and Mac clients (such as from chats) and from the Microsoft Teams web app shows the file names correctly.
• While we’re focused on remediation, users can use the “Open in SharePoint” option at the top of the Microsoft Teams desktop and Mac clients, which will allow the files to be downloaded with the correct names from SharePoint Online.
• ・Current status : We’ve identified that the UTF-8 encoded characters in the name are duplicating, causing impact to Microsoft Teams desktop clients file downloads.
• We’re continuing to review Microsoft Teams diagnostic logs to help us identify the root cause of the duplication issue in order to formulate a remediation plan.
• ・Scope of impact : This issue may affect any users who download files with UTF-8 encoded characters in the name from channels in the Microsoft Teams desktop clients.
• ・Next update by: Thursday, October 13, 2022, 10:30 PM (1:30 PM UTC)

October 13, 2022 2:44 PM – Service restored

• ・Title : Users may see distorted file names when downloading files that have UTF-8 encoded characters in the name
• ・User Impact : Users may see distorted file names when downloading files with UTF-8 encoded characters in the name.
• ・More info : The impact only occurs when the files have UTF-8 encoded characters in the name, and are downloaded from channels in the Microsoft Teams desktop and Mac clients.
• Downloading files elsewhere in the Microsoft Teams desktop and Mac clients (such as from chats) and from the Microsoft Teams web app shows the file names correctly.
• While we’re focused on remediation, users can use the “Open in SharePoint” option at the top of the Microsoft Teams desktop and Mac clients, which will allow the files to be downloaded with the correct names from SharePoint Online.
• ・Current status : We’re analyzing network trace logs and Microsoft Teams diagnostics logs provided by some affected users to identify the source of the encoding issue so we can develop a fix.
• ・Scope of impact : This issue may affect any users who download files with UTF-8 encoded characters in the name from channels in the Microsoft Teams desktop and Mac clients.
• ・Next update by: Thursday, October 13, 2022, 6:00 PM (9:00 AM UTC)

October 13, 2022 2:15 PM – Service restored

• ・Title : Users may see distorted file names when downloading files that have UTF-8 encoded characters in the name
• ・User Impact : Users may see distorted file names when downloading files with UTF-8 encoded characters in the name.
• ・More info : The impact only occurs when the files have UTF-8 encoded characters in the name, and are downloaded from channels in the Microsoft Teams desktop and Mac clients.
• Downloading files elsewhere in the Microsoft Teams desktop and Mac clients (such as from chats) and from the Microsoft Teams web app shows the file names correctly.
• While we’re focused on remediation, users can use the “Open in SharePoint” option at the top of the Microsoft Teams desktop and Mac clients, which will allow the files to be downloaded with the correct names from SharePoint Online.
• ・Current status : We’re investigating a potential issue and checking for impact to your organization. We’ll provide an update within 30 minutes.
• ・Scope of impact : This issue may affect any users who download files with UTF-8 encoded characters in the name from channels in the Microsoft Teams desktop and Mac clients.

Microsoft Teams とは？

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関連リンク

• ・Microsoft Teams｜リモート ワークのためのコラボレーション ツール：https://www.microsoft.com/ja-jp/microsoft-365/microsoft-teams/group-chat-software
• ・日本マイクロソフト – Official Home Page：https://www.microsoft.com/ja-jp

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