Users may be unable to reply to email messages from a pop-up window in Outlook on the web

Title: Users may be unable to reply to email messages from a pop-up window in Outlook on the web User impact: Users may have been unable reply to email messages from a pop-up window in Outlook on the web. More info: This issue may have occurred within any browser and impacted single reply and reply all functions. While we were focused on remediation, user testing indicated that by changing browser-specific pop-up settings to ensure that pop-ups were allowed, affected users may have been able to avoid impact. Final status: We've confirmed through testing with a subset of affected users that the impact has been remediated. Affected users may need to refresh their Outlook on the web session to have the changes saturate. Scope of impact: Users attempting to reply to email messages from a pop-up window in Outlook in the web may have been impacted. Start time: Tuesday, April 14, 2026, at 2:00 AM UTC End time: Thursday, April 30, 2026, at 3:21 PM UTC Root cause: A fix to address an unrelated issue introduced a code issue that’s leading to the impact. Next steps: - We're reviewing offending fix to understand why impact to reply functionality wasn't caught during the testing phase. This will allow us to drive service improvements by proactively identifying similar issues in the future and improve our update testing processes. This is the final update for the event.

Title: Users may be unable to reply to email messages from a pop-up window in Outlook on the web User impact: Users may be unable reply to email messages from a pop-up window in Outlook on the web. More info: This issue may occur within any browser and impacts single reply and reply all functions. While we're focused on remediation, user testing indicates that by changing browser-specific pop-up settings to ensure that pop-ups are allowed, affected users may be able to avoid impact. Current status: We’ve received positive reports from our initial validations and we’re continuing to test with affected users to ensure the issue is fully resolved. Scope of impact: Users attempting to reply to email messages from a pop-up window in Outlook in the web may be impacted. Start time: Tuesday, April 14, 2026, at 2:00 AM UTC Root cause: A fix to address an unrelated issue introduced a code issue that’s leading to the impact. Next update by: Friday, May 01, 2026, at 10:30 PM UTC

Title: Users may be unable to reply to email messages from a pop-up window in Outlook on the web User impact: Users may be unable reply to email messages from a pop-up window in Outlook on the web. More info: This issue may occur within any browser and impacts single reply and reply all functions. While we're focused on remediation, user testing indicates that by changing browser-specific pop-up settings to ensure that pop-ups are allowed, affected users may be able to avoid impact. Current status: We've completed the deployment of our fix and validations within our internal test environment indicate it's functioning as expected. We're continuing to test with a subset of affected users to ensure the issue is fully resolved. Scope of impact: Users attempting to reply to email messages from a pop-up window in Outlook in the web may be impacted. Start time: Tuesday, April 14, 2026, at 2:00 AM UTC Root cause: A fix to address an unrelated issue introduced a code issue that’s leading to the impact. Next update by: Friday, May 01, 2026, at 5:00 AM UTC

Title: Users may be unable to reply to email messages from a pop-up window in Outlook on the web User impact: Users may be unable reply to email messages from a pop-up window in Outlook on the web. More info: This issue may occur within any browser and impacts single reply and reply all functions. While we're focused on remediation, user testing indicates that by changing browser-specific pop-up settings to ensure that pop-ups are allowed, affected users may be able to avoid impact. Current status: We’re continuing to monitor our fix deployment as it saturates throughout the affected environments. As this saturation nears completion, we’re continuing our validation efforts to verify the fix's efficacy with a subset of affected users and within our internal environments. We expect that this deployment process will be completed in full by our next scheduled update. Scope of impact: Users attempting to reply to email messages from a pop-up window in Outlook in the web may be impacted. Start time: Tuesday, April 14, 2026, at 2:00 AM UTC Root cause: A fix to address an unrelated issue introduced a code issue that’s leading to the impact. Next update by: Thursday, April 30, 2026, at 6:00 PM UTC

Title: Users may be unable to reply to email messages from a pop-up window in Outlook on the web User impact: Users may be unable reply to email messages from a pop-up window in Outlook on the web. More info: This issue may occur within any browser and impacts single reply and reply all functions. While we're focused on remediation, user testing indicates that by changing browser-specific pop-up settings to ensure that pop-ups are allowed, affected users may be able to avoid impact. Current status: We’re continuing deployment of the fix across the affected environments. In parallel, we’re continuing our validation efforts as deployment progresses with affected users and within our internal environments to verify efficacy and ensure successful resolution. Scope of impact: Users attempting to reply to email messages from a pop-up window in Outlook in the web may be impacted. Start time: Tuesday, April 14, 2026, at 2:00 AM UTC Root cause: A fix to address an unrelated issue introduced a code issue that’s leading to the impact. Next update by: Monday, April 27, 2026, at 6:00 PM UTC

Title: Users may be unable to reply to email messages from a pop-up window in Outlook on the web User impact: Users may be unable reply to email messages from a pop-up window in Outlook on the web. More info: This issue may occur within any browser and impacts single reply and reply all functions. While we're focused on remediation, user testing indicates that by changing browser-specific pop-up settings to ensure that pop-ups are allowed, affected users may be able to avoid impact. Current status: We’ve identified that the fix is taking longer than expected to reach full saturation across the affected environments. We’re continuing deployment while validating its progress to ensure successful completion. In parallel, we’re conducting additional testing with affected users and within our internal environments to validate successful resolution of the issue. Scope of impact: Users attempting to reply to email messages from a pop-up window in Outlook in the web may be impacted. Start time: Tuesday, April 14, 2026, at 2:00 AM UTC Root cause: A fix to address an unrelated issue introduced a code issue that’s leading to the impact. Next update by: Thursday, April 23, 2026, at 5:30 PM UTC

Title: Users may be unable to reply to email messages from a pop-up window in Outlook on the web User impact: Users may be unable reply to email messages from a pop-up window in Outlook on the web. More info: This issue may occur within any browser and impacts single reply and reply all functions. While we're focused on remediation, user testing indicates that by changing browser-specific pop-up settings to ensure that pop-ups are allowed, affected users may be able to avoid impact. Current status: After applying the fix and receiving initial reports from users that are no longer prevented from replying to email messages from the pop-up window in Outlook on the web, we're conducting additional testing with affected users to validate that the problems have been universally resolved. Scope of impact: Users attempting to reply to email messages from a pop-up window in Outlook in the web may be impacted. Start time: Tuesday, April 14, 2026, at 2:00 AM UTC Root cause: A fix to address an unrelated issue introduced a code issue that’s leading to the impact. Next update by: Wednesday, April 22, 2026, at 5:30 PM UTC

Title: Users may be unable to reply to email messages from a pop-up window in Outlook on the web User impact: Users may be unable reply to email messages from a pop-up window in Outlook on the web. More info: This issue may occur within any browser and impacts single reply and reply all functions. While we're focused on remediation, user testing indicates that by changing browser-specific pop-up settings to ensure that pop-ups are allowed, affected users may be able to avoid impact. Current status: We’ve received confirmation from a subset of affected users that the issue appears to be mitigated following the applied fix. We’re awaiting confirmation from the remaining users to ensure the issue is fully resolved across all impacted infrastructures. Scope of impact: Users attempting to reply to email messages from a pop-up window in Outlook in the web may be impacted. Start time: Tuesday, April 14, 2026, at 2:00 AM UTC Root cause: A fix to address an unrelated issue introduced a code issue that’s leading to the impact. Next update by: Tuesday, April 21, 2026, at 5:30 PM UTC

Title: Users may be unable to reply to email messages from a pop-up window in Outlook on the web User impact: Users may be unable reply to email messages from a pop-up window in Outlook on the web. More info: This issue may occur within any browser and impacts single reply and reply all functions. While we're focused on remediation, user testing indicates that by changing browser-specific pop-up settings to ensure that pop-ups are allowed, affected users may be able to avoid impact. Current status: We’re continuing to validate and confirm with affected users to ensure that the issue is resolved. Scope of impact: Users attempting to reply to email messages from a pop-up window in Outlook in the web may be impacted. Start time: Tuesday, April 14, 2026, at 2:00 AM UTC Root cause: A fix to address an unrelated issue introduced a code issue that’s leading to the impact. Next update by: Tuesday, April 21, 2026, at 8:30 AM UTC

Title: Users may be unable to reply to email messages from a pop-up window in Outlook on the web User impact: Users may be unable reply to email messages from a pop-up window in Outlook on the web. More info: This issue may occur within any browser and impacts single reply and reply all functions. While we're focused on remediation, user testing indicates that by changing browser-specific pop-up settings to ensure that pop-ups are allowed, affected users may be able to avoid impact. Current status: We’ve reached out to a subset of affected users to validate if this issue is fully resolved following our successful fix deployment. Scope of impact: Users attempting to reply to email messages from a pop-up window in Outlook in the web may be impacted. Start time: Tuesday, April 14, 2026, at 2:00 AM UTC Root cause: A fix to address an unrelated issue introduced a code issue that’s leading to the impact. Next update by: Tuesday, April 21, 2026, at 4:00 AM UTC

Title: Users may be unable to reply to email messages from a pop-up window in Outlook on the web User impact: Users may be unable reply to email messages from a pop-up window in Outlook on the web. More info: This issue may occur within any browser and impacts single reply and reply all functions. While we're focused on remediation, user testing indicates that by changing browser-specific pop-up settings to ensure that pop-ups are allowed, affected users may be able to avoid impact. Current status: We’ve confirmed that our fix deployment has fully saturated throughout the affected infrastructure and are reaching out to affected users to validate if this has remediated all impact as expected.  Scope of impact: Users attempting to reply to email messages from a pop-up window in Outlook in the web may be impacted. Start time: Tuesday, April 14, 2026, at 2:00 AM UTC Root cause: A fix to address an unrelated issue introduced a code issue that’s leading to the impact. Next update by: Monday, April 20, 2026, at 7:30 PM UTC

Title: Users may be unable to reply to email messages from a pop-up window in Outlook on the web User impact: Users may be unable reply to email messages from a pop-up window in Outlook on the web. More info: This issue may occur within any browser and impacts single reply and reply all. While we're focused on remediation, user testing indicates that by changing browser-specific pop-up settings to ensure that pop-ups are allowed, affected users may be able to avoid impact. Current status: We’re monitoring the status of our deployment to ensure the issue is resolved as expected by our next scheduled update. Scope of impact: Users attempting to reply to email messages from a pop-up window in Outlook in the web may be impacted. Start time: Tuesday, April 14, 2026, at 3:35 PM UTC Root cause: A fix to address an unrelated issue introduced a code issue that’s leading to the impact. Next update by: Monday, April 20, 2026, at 5:30 PM UTC

Title: Users may be unable to reply to email messages from a pop-up window in Outlook on the web User impact: Users may be unable reply to email messages from a pop-up window in Outlook on the web. More info: This issue may occur within any browser and impacts single reply and reply all. While we're focused on remediation, user testing indicates that by changing browser-specific pop-up settings to ensure that pop-ups are allowed, affected users may be able to avoid impact. Current status: We’ve determined that a fix deployment to address an unrelated problem introduced a code issue that is leading to the impact. We’ve initiated the process of deploying a fix to address this problem and will provide an estimation for the completion of this process when available. Scope of impact: Users attempting to reply to email messages from a pop-up window in Outlook in the web may be impacted. Start time: Tuesday, April 14, 2026, at 3:35 PM UTC Root cause: A fix deployment to address an unrelated issue introduced a code issue that is leading to the impact. Next update by: Saturday, April 18, 2026, at 12:30 AM UTC

Title: Users may be unable to reply to email messages from a pop-up window in Outlook on the web User impact: Users may be unable reply to email messages from a pop-up window in Outlook on the web. More info: This issue may occur within any browser and impacts single reply and reply all. While we're focused on remediation, user testing indicates that by changing browser-specific pop-up settings to ensure that pop-ups are allowed, affected users may be able to avoid impact. Current status: We're further reviewing the aforementioned code change which we expect is causing the issue to validate our next troubleshooting actions. Scope of impact: Users attempting to reply to email messages from a pop-up window in Outlook in the web may be impacted. Next update by: Friday, April 17, 2026, at 10:30 PM UTC

Title: Users may be unable to reply to email messages from a pop-up window in Outlook on the web User impact: Users may be unable reply to email messages from a pop-up window in Outlook on the web. More info: This issue may occur within any browser and impacts single reply and reply all. While we're focused on remediation, user testing indicates that by changing browser-specific pop-up settings to ensure that pop-ups are allowed, affected users may be able to avoid impact. Current status: We're continuing to review the code change which we expect is causing the issue to determine the most efficient method to remediate the impact. Scope of impact: Users attempting to reply to email messages from a pop-up window in Outlook in the web may be impacted. Next update by: Friday, April 17, 2026, at 5:30 AM UTC

Title: Users may be unable to reply to email messages from a pop-up window in Outlook on the web User impact: Users may be unable reply to email messages from a pop-up window in Outlook on the web. More info: This issue may occur within any browser and impacts single reply and reply all. While we're focused on remediation, user testing indicates that by changing browser-specific pop-up settings to ensure that pop-ups are allowed, affected users may be able to avoid impact. Current status: We've identified that a recent code change rolled out to address an unrelated issue affecting the reply button in Outlook on the web appears to be the source of impact. We're proceeding with additional investigation and analysis to verify our findings as we work towards developing a comprehensive fix to prevent further impact. Scope of impact: Users attempting to reply to email messages from a pop-up window in Outlook in the web may be impacted. Next update by: Thursday, April 16, 2026, at 9:30 PM UTC

Title: Users may be unable to reply to email messages from a pop-up window in Outlook on the web User impact: Users may be unable reply to email messages from a pop-up window in Outlook on the web. More info: This issue may occur within any browser and would impact single reply and reply all. Current status: We're reviewing the diagnostic data provided by affected users to help determine our next troubleshooting steps. Scope of impact: Users attempting to reply to email messages from a pop-up window in Outlook in the web may be impacted. Next update by: Wednesday, April 15, 2026, at 11:30 PM UTC

Title: Users may be unable to reply to email messages from a pop-up window in Outlook on the web User impact: Users may be unable reply to email messages from a pop-up window in Outlook on the web. More info: This issue may occur within any browser and would impact single reply and reply all. Current status: We're investigating a potential issue with Exchange Online and checking for impact to your organization. We'll provide an update within 30 minutes.