Microsoft 365 administration reference for Entra identity, Exchange Online, SharePoint/OneDrive, Teams, Intune, PowerShell
Identity & sign-in
Distinguish UPN, primary SMTP address and aliases.
Repeated prompts may come from session, Conditional Access or device state.
Keep Correlation ID, error and Conditional Access result.
Revocation can interrupt all user clients.
Microsoft Graph PowerShell
Connect-MgGraph -Scopes "User.Read.All","Directory.Read.All"Request only required scopes.
Get-MgUser -UserId user@example.com -Property Id,DisplayName,UserPrincipalName,AccountEnabledChecks identity and account state.
Get-MgUserMemberOf -UserId user@example.comReturns varied directory objects; filter as needed.
Get-MgContextChecks tenant, account and scopes before sensitive operations.
Exchange Online
Connect-ExchangeOnlineUse a current ExchangeOnlineManagement module.
Get-Mailbox user@example.com | Format-List DisplayName,PrimarySmtpAddress,RecipientTypeDetailsChecks recipient type and primary SMTP.
Get-Mailbox user@example.com | Select-Object -ExpandProperty EmailAddressesShows aliases/proxy addresses.
Get-MailboxStatistics user@example.com | Select DisplayName,TotalItemSize,ItemCount,LastLogonTimeCorrelate with configured quotas and archive.
Message tracing
Get-MessageTraceV2 -SenderAddress user@example.com -StartDate (Get-Date).AddHours(-24) -EndDate (Get-Date)Use the trace cmdlet supported by your module/tenant.
Excellent identifier for correlating transport and headers.
Full enhanced status and generating server guide diagnosis.
Mail may reach tenant transport but still be quarantined.
SharePoint & OneDrive
Do not assume the displayed URL is the actual file path.
Invalid names/paths can block only part of the sync set.
The most restrictive applicable policy wins.
Check both recycle-bin stages before complex recovery.
Teams
Teams issues may originate in identity or licensing.
Compare clients before destructive cache cleanup.
Teams relies on other M365 services for several features.
Media requirements vary; use current Microsoft recommendations.
Intune & devices
Separate Entra join, enrollment and compliance problems.
Allow reporting time before repeating actions.
Sign-in logs show applied policies.
Confirm exact scope before executing destructive actions.
DNS & tenant security
Resolve-DnsName exemple.fr -Type MXChecks external inbound routing.
Resolve-DnsName exemple.fr -Type TXTCheck Microsoft and third-party sending sources.
Resolve-DnsName _dmarc.exemple.fr -Type TXTChecks policy and reporting.
Check Microsoft service incidents before deep troubleshooting.
Key points
- Always distinguish UPN, primary SMTP and aliases.
- For sign-in failures, keep Correlation ID, Request ID, UTC timestamp and Conditional Access result.
- Request the minimum Graph/PowerShell scopes needed.
- Security actions such as revoke sessions, wipe or retire should be explicitly validated before execution.