Moving to cloud-only IT can reduce the number of systems you maintain, but buying Microsoft 365 E3 or E5 does not remove your dependence on Active Directory. The deciding question is whether your applications, devices, and working practices can operate without it.
For a small business, start with a dependency list and a pilot group. Choose licenses after you know which controls you need and who will operate them.
What cloud-only means in this plan
This article uses cloud-only to mean cloud-managed identities and endpoints, without an on-premises directory required for routine sign-in. Moving a server into an Azure virtual machine is a different change: you still have a server to maintain.
Microsoft distinguishes Entra joined endpoints from hybrid joined endpoints. A hybrid joined device still has an on-premises Active Directory relationship. Inventory those relationships before deciding what can be retired.
Check dependencies before removing a domain controller
List each system, its owner, and the authentication method it uses. Pay particular attention to:
- Applications using LDAP, Kerberos, or Windows integrated authentication.
- File shares, printers, certificate services, and network authentication.
- Group Policy settings that need an equivalent device-management policy.
- Service accounts, scheduled tasks, and integrations running on local servers.
- Remote access and locations with unreliable internet connectivity.
For each dependency, record whether you will replace it, migrate it, or retain it. A single application can justify keeping part of a hybrid environment. That is a planning constraint, rather than a reason to rush an unsupported workaround.
Compare E3 and E5 against the work you need to do
Avoid a feature checklist that treats every security product as the same thing. For example, Microsoft's Defender service description lists Defender for Endpoint Plan 1 with Microsoft 365 E3 and Plan 2 with Microsoft 365 E5. E3 should not be described as having no Defender for Endpoint coverage.
For each proposed license, write down:
- The capability you need, such as a specific endpoint investigation feature.
- Which subscription or add-on provides it for the intended users.
- Who will configure it and review its alerts.
- Which existing product it could replace, after testing.
Check current product terms and your agreement before purchase. Microsoft 365 E3, Office 365 E3, and similarly named offers are not interchangeable. Prices, included services, and add-ons should be confirmed with your supplier rather than copied from an old article.
Pilot a complete working day
Test more than a successful sign-in. Include device enrollment, application access, printing, file access, password recovery, and a lost-device scenario. Involve people from different roles, especially anyone using older software or working away from the main office.
Keep an issue list with an owner and a resolution for each problem. Document how to restore access if a device policy or authentication change blocks someone. Test emergency administrator access separately from normal user access.
Retire infrastructure only after the pilot passes
Use a written cutover checklist: dependencies resolved, data backed up, recovery tested, responsibilities assigned, and users informed. Remove old access paths and redundant tools only when you have confirmed their replacements work.
Cloud management changes the maintenance workload; it does not remove patching, backups, access reviews, or incident response. Compare the full operating cost, including migration effort and ongoing administration, before making the final decision.
For the access side of the project, see how to review accumulated permissions. If you need help mapping the dependencies, discuss your environment with OpenTech Consulting.