Description	We are currently investigating intermittent errors during folder uploads and synchronization. In some cases, uploads or sync operations may fail and need to be retried. Existing files remain accessible. We are working on resolving the issue.
Affected users	All users of bwSync&Share.
Exists since	2026-06-23 10:00

Description	Mitigation for Exchange Server vulnerability (critical zero day exploit) causes issues. These restrictions are temporary until a regular security update is released. - OWA Print Calendar functionality might not work. As a workaround copy the data or screenshot the calendar you want to print or use Outlook Desktop client. - Inline images might not display correctly in the recipients OWA reading pane. As a workaround, send images as email attachments or use Outlook Desktop client. - Published calendars might not work with error 500. - OWA light https://support.microsoft.com/en-us/office/learn-more-about-the-light-version-of-outlook-2aec8c2d-da48-4707-ba37-c800e1c284cd) does not work properly. ==> Users are unable to switch back to standard version of OWA. We will make the necessary changes for all affected users on the server side.
Affected users	Users using https://owa.kit.edu
Exists since	2026-05-14 19:00

AFFECTED:

• SB: Microsoft OneDrive for Business - Tenant KIT0
• SB: Microsoft SharePoint Online - Tenant KIT0

IMPACT: No interruptions.

REASON:
Configuration change

DESCRIPTION:
Microsoft is changing the authentication method external users use to access content shared through OneDrive and SharePoint Online.

The previous SharePoint Online One-Time Passcode (OTP) method will be retired and replaced by Microsoft Entra B2B authentication.

What is changing?
Previously, external users could access shared content by signing in with a SharePoint Online One-Time Passcode (OTP) sent to their email address. Microsoft is moving this process to Microsoft Entra B2B.

Timeline:

• Starting in July 2026, SharePoint Online One-Time Passcode (OTP) authentication will be gradually retired.
• The transition is expected to be completed by August 31, 2026.

Impact on existing sharing links:

• External users who already have a Microsoft Entra B2B guest account will not be affected by this change.
• External users who do not yet have a Microsoft Entra B2B guest account may no longer be able to access content that was previously shared with them after the retirement begins in July 2026. In this case, an access denied message may appear.
• To restore access, it is sufficient to re-share a file or folder with the affected user using the same email address. This creates the required guest account.
• If an external user uses multiple sharing links, re-sharing a single item is sufficient. After that, all previously shared links for this user will work again.

Impact on new sharing links: New sharing links created after the transition will automatically use Microsoft Entra B2B authentication.

What do you need to do?
In most cases, no action is required. If an external user can no longer access shared content after July 2026, simply re-share a file or folder with the same external email address. After that, access to all previously shared content will be restored.

Further information:
https://learn.microsoft.com/en-us/sharepoint/faqs-odspintegrationwithentrab2b
https://office365itpros.com/2026/03/06/guest-accounts-spo/
https://office365itpros.com/2025/06/10/entra-id-b2b-collaboration-spo/
https://mc.merill.net/message/MC1243549