Microsoft Entra Connect sync stopped, request upgrade and library not found
Hello, I have the latest (for our company, present on Entra blade) version of Microsoft Entra Connect Sync: 4 days ago I noticed on Synchronization Service Manager that there is no sync of data; I have started the Microsoft Entra Connect Sync and found a big button with "Upgrade" word; I tried to execute the upgrade but when the it arrives to the Connect to Microsoft Entra ID step, I fill with my global administrator account but found a stop error: An error occured while retrieving the Active Directory schema. The error was: Could not load file or assembly 'file:///C:\Program Files\Microsoft Azure AD Sync\Bin\Microsoft.IdentityModel.Clients.ActiveDirectory.dll' or one of its dependencies. The system cannot find the file specified. and when I click again on Next I have the same request of global administrator user and password and the same error. Now, the library is not present but I verified, in a test tenant where I have a working Entra Connect Sync system, that the files is not present even there (and also when I start Microsoft Connect Entra Sync I haven't the upgrade button there); I also tried to repair the installation, but obviously the file is no there. What can I do? Are there other people with the same issue? Any idea is appreciated.Architecting Microsoft 365 Environments for Multi-National Enterprises: Lessons from the Field
Introduction In today’s global economy, enterprises rely on Microsoft 365 to empower seamless collaboration across borders. However, deploying and securing multi-national M365 environments introduces complex technical, operational, and compliance challenges. With over two decades architecting cloud environments across the Americas, EMEA and APAC, I’ve led numerous deployments and migrations requiring hybrid identity resilience, data sovereignty compliance, and global operational continuity. This article presents field-tested lessons and strategic best practices to guide architects and IT leaders in designing robust, compliant, and scalable Microsoft 365 environments for multi-national operations. Key Challenges in Multi-National M365 Deployments 1. Hybrid Identity Complexity Managing synchronization between on-premises Active Directory and Azure AD becomes exponentially complex across regions. https://learn.microsoft.com/en-us/azure/active-directory/hybrid/whatis-hybrid-identity can introduce replication delays and login failures if not properly planned. Tip: Always assess latency impact on Kerberos authentication, token issuance, and Azure AD Connect synchronization cycles. 2. Data Residency and Compliance Many countries enforce strict data sovereignty laws restricting where personal and sensitive data can reside. Selecting tenant regions and enabling https://learn.microsoft.com/en-us/microsoft-365/enterprise/microsoft-365-multi-geo?view=o365-worldwide become critical to avoid compliance violations. Impact Example: A financial institution with European operations faced potential GDPR breaches until Multi-Geo was implemented to ensure Exchange Online and OneDrive data remained within EU boundaries. 3. Licensing and Cost Control Balancing E3, E5, and F3 licenses across countries with varying user roles and local currencies adds administrative and financial complexity. Best Practice: Implement https://learn.microsoft.com/en-us/azure/active-directory/enterprise-users/licensing-groups-assign, aligning assignments with security groups mapped to user personas. 4. Secure Collaboration Across Borders External sharing in SharePoint, OneDrive, and Teams federation introduces security risks if not precisely configured. Default sharing settings often exceed local compliance requirements, risking data leakage. Lesson Learned: Always validate external sharing policies against each country’s data protection laws and client contractual agreements. 5. Operational Support and SLA Alignment Global operations require support models beyond single-region business hours, demanding proactive incident response and escalation planning. Example: Implementing follow-the-sun support with regional admins trained on Microsoft 365 admin centers and PowerShell mitigates downtime risks. Strategic Solutions and Best Practices 1. Architect Hybrid Identity with Redundancy Deploy https://learn.microsoft.com/en-us/entra/identity/hybrid/connect/how-to-connect-sync-staging-server in alternate datacenters. Implement Password Hash Sync to reduce dependency on VPN and WAN availability for authentication. 2. Utilize Microsoft 365 Multi-Geo Capabilities Leverage https://learn.microsoft.com/en-us/microsoft-365/enterprise/microsoft-365-multi-geo?view=o365-worldwide to meet data residency requirements per geography. Validate licensing implications and admin configurations for each satellite location. 3. Segment Licensing by User Persona Define clear user personas (executives, knowledge workers, frontline staff). Map license types accordingly, optimizing costs while ensuring productivity needs are met. Use https://learn.microsoft.com/en-us/azure/active-directory/enterprise-users/licensing-groups-assign for scalable management. 4. Design Conditional Access Policies by Geography Create https://learn.microsoft.com/en-us/azure/active-directory/conditional-access/location-condition. Integrate with Intune compliance policies to block or limit access for non-compliant devices. 5. Implement a Global Governance Model Establish clear local vs. global admin roles to maintain accountability. Enforce https://learn.microsoft.com/en-us/azure/active-directory/privileged-identity-management/pim-configure to control and audit privileged access. Lessons Learned from the Field Latency is a silent killer – Always test Microsoft Teams and OneDrive performance across regions before production rollouts. Communication is critical – Local IT teams must align early with global security and compliance strategies. Compliance first – Never assume Microsoft’s default data location suffices for local regulations. Cost optimization is ongoing – Conduct license audits and adjust assignments every six months. Conclusion Architecting Microsoft 365 for a multi-national enterprise demands strategic integration of compliance, hybrid identity resilience, secure collaboration, and cost optimization. Cloud success in a global enterprise is not an accident – it is architected. By applying these best practices validated against Microsoft recommendations and real-world deployments, organizations can empower global collaboration without sacrificing governance or security. About the Author Gonzalo Brown Ruiz is a Senior Office 365 Engineer with over 21 years architecting secure, compliant cloud environments across North America, Latin America, EMEA and APAC. He specializes in Microsoft Purview, Entra ID, Exchange Online, eDiscovery, and enterprise cloud security.
MTO and access to on premises file system
Let me preface this by saying I'm still fairly new to 365 Admin (it's been a steep learning curve) and haven't even got my feet wet with on premises stuff as yet. Also, I think some of the admin decisions made previously by others may have been based on just repeating what was found to work the first time rather than necessarily a deep understanding of the best solution. The situation when I arrived on the scene was this (actually it was a bit more complex and messy than this, but this simplified description covers the salient points at this stage) One tenant, with two domains, call them old-domain and new-domain. Two types of user, who I will refer to operations and corporate. An on premises Active Directory system running a file server. Well to be more precise on three premises with mirroring of data and a DFS, but from the user perspective when you're one of the office locations and connect to the network the same folders are available to you. Everyone was using Azure Joined Company Laptops to do this, so their laptop logins were also their network logins. Outside of the offices people connected to the DFS using a VPN (with three gateways in different countries). Operations Users had one account, @old-domain, this was licensed for 365 and had a mailbox associated with it. It was also synched to their on premises AD account Corporate Users had two accounts, one @old-domain with no license, synched to an on premises AD account. The second was new-domain with a 365 license and mailbox. If you're scratching your head wondering why two accounts rather than assigning the new-domain email address to the same account, I can't give you a definitive answer as I've never been given one, but for whatever reason when new domains were brought into play on corporate name changes the admins gave them new mailboxes rather than simply aliasing email addresses to the same mailbox (some people had three accounts as a result). What I did note was that when a new Corporate user was added the admins gave them both of the above accounts, I was told that the unlicensed old-domain one was required for the access to the DFS. Now for reasons not worth getting into here, a decision was made to move the Corporate users to a new tenant, along with new-domain and then to link the two tenants in a multi-tenant organization. It was also decided to leverage BYOD for Corporate users, so their devices will only be Azure registered. This has been done, there was some pain thanks to the reluctance of Microsoft applications to switch to the new account locations rather than redirecting back to the old tenant, but that's been sorted. So right now Corporate users still have two accounts, but on two tenants. On the Old Tenant they have their @old-domain account, no license, no mailbox, synched to the on premises AD (as before) On the New Tenant they have their new-domain account. This is where they actually do their work, and is the only account anyone should be communicating with internally or externally. Access to the DFS is being done using the VPN with the on premises credentials associated with the old-domain account. In terms of functionality, this works perfectly well, people across the two tenants appear in each other's address lists, they can chat and share information etc. Everybody also has access to the folders they should have access to on the DFS. However there are two issues. The first, and most detrimental in terms of just getting work done is that users in one of the overseas offices have found their access to the DFS has slowed considerably, despite being in physically the same location as the data. I believe the problem is that although the data is on-premises, the VPN gateway is not, therefore data does a round trip from the server, through that gateway IP address at the ISP and back to the user. Since they are in a remote location with poor internet this slows things considerably. So the first question is, how do we take that loop out of the equation so that when they are in the office they connect more directly to the servers on site? Ideally without having to revert to needing an Azure AD joined device. The second issue is that those remaining old-domain accounts (the ones for the Corporate users who are now working on the new tenant) on the old tenant are messy, in two ways 1) From an admin perspective, because every one of those corporate users still has two accounts, their local one that is synched to On Premises AD, and the the external account shared from the new tenant as part of the MTO 2) From a user's perspective. For reasons that I cannot fathom (but this is coming direct from Microsoft after many attempts on my part to find a way) it seems that while you can control which licensed accounts appear on Teams search by controlling whether they are in the GAL and setting the appropriate switch in Teams Admin, all the unlicensed users appear whether you like it or not. The net result is that when someone on the old tenant starts typing in a name of someone in Corporate, they get two suggestions coming up. So the second question is, are those accounts actually necessary?
Adding Proxy Addresses in AD Before Tenant-to-Tenant Migration Cutover
We're in the process of migrating users from another M365 tenant into our own, which is synced with on-prem AD. Before the cutover, we'd like to add the proxy addresses from the source tenant to our AD and have them sync to the cloud once the domain is added to our M365 tenant. Would this work as expected, or are there any potential issues to be aware of?
User able to send mail with account locked
Hello and Happy New Year! I tried to go through the official M365 support channels on this issue, but they were unable to help me. Environment: Local Active Directory synced to Azure/M365 via Azure AD Connect All user mailboxes reside on Exchange Online We found out, via a external security audit, that we had an user account, which was both locked and had an expired password, that was still able to send email out via the iOS Outlook app. We were under the impression that if an account was locked that they could still receive email, but not send. The account was for an employee that is no longer active and thus has been archived and deleted. We are just hoping for an explanation/root cause of this and how we can hopefully prevent it from happening in the future. Thank you, Tony Martinac AMIC
Remove On Premises exchange Hybrid and go fully Online
Hello, I currently have a scenario where there is a Hybrid Exchange environment with 1 server. All my mailboxes have been migrated online. I would like to completely remove dependency on local AD and I do not care about AD synchronization. How do I "tell" the O365 tenant not function on it's own so that I can manage 100% from 365 Administration? I do understand that my MX and other DNS records will need to be changed. Are there any solid guides out there on decommissioning the on premise exchange server. I want to do this with the least impact on users. Thanks, Keith
Address rewrite not working for Calendar items
Hi, We are running a hybrid environment with 3 active directory domains, 3 on-prem Exchange clusters and the majority of our mailboxes in O365. We have set up a default address rewrite so that emails from everyone across the 3 different legacy domain names appear to come from the new domain name. Emails are sent from O365 back to the on-prem clusters for rewriting. Lets use an example john@oldcompany1.com john@oldcompany2.com john@oldcompany3.com Address rewrite is set up so all emails from the above addresses are displayed to external recipients as: john@newcompanyname.com This works perfectly for all outbound emails, however it does not work with meeting/calendar invites. For example, my own mailbox has the default alias of @oldcompany1.com, and when I send an email to a recipient outside of our organisation, it shows as coming from @newcompanyname.com, but when I send a meeting/appointment to an external recipient, it shows as coming from @oldcompany1.com. Has anyone seen this before, if so - do you have any tips on where to start the troubleshooting process?
