Need to Restore PST Files to Office 365 Mailboxes - What's the Best Approach
Hey everyone, I have a task coming up where I need to restore several PST files back into Office 365 mailboxes. Haven't done this before at this scale and honestly not sure where to begin. I've looked at Microsoft's native import service through Purview but I have a few concerns: Some of the PST files are quite large — not sure how well it handles that I need to restore only specific folders for some users, not the entire PST I'm worried about data consistency after the restore Would prefer something that doesn't require too many admin roles or complex setup For those who have done PST to Office 365 restores — what approach worked best for you? Any tools, tips, or things to watch out for that you wish you knew before starting?I built a free, open-source M365 security assessment tool - looking for feedback
I work as an IT consultant, and a good chunk of my time is spent assessing Microsoft 365 environments for small and mid-sized businesses. Every engagement started the same way: connect to five different PowerShell modules, run dozens of commands across Entra ID, Exchange Online, Defender, SharePoint, and Teams, manually compare each setting against CIS benchmarks, then spend hours assembling everything into a report the client could actually read. The tools that automate this either cost thousands per year, require standing up Azure infrastructure just to run, or only cover one service area. I wanted something simpler: one command that connects, assesses, and produces a client-ready deliverable. So I built it. What M365 Assess does https://github.com/Daren9m/M365-Assess is a PowerShell-based security assessment tool that runs against a Microsoft 365 tenant and produces a comprehensive set of reports. Here is what you get from a single run: 57 automated security checks aligned to the CIS Microsoft 365 Foundations Benchmark v6.0.1, covering Entra ID, Exchange Online, Defender for Office 365, SharePoint Online, and Teams 12 compliance frameworks mapped simultaneously -- every finding is cross-referenced against NIST 800-53, NIST CSF 2.0, ISO 27001:2022, SOC 2, HIPAA, PCI DSS v4.0.1, CMMC 2.0, CISA SCuBA, and DISA STIG (plus CIS profiles for E3 L1/L2 and E5 L1/L2) 20+ CSV exports covering users, mailboxes, MFA status, admin roles, conditional access policies, mail flow rules, device compliance, and more A self-contained HTML report with an executive summary, severity badges, sortable tables, and a compliance overview dashboard -- no external dependencies, fully base64-encoded, just open it in any browser or email it directly The entire assessment is read-only. It never modifies tenant settings. Only Get-* cmdlets are used. A few things I'm proud of Real-time progress in the console. As the assessment runs, you see each check complete with live status indicators and timing. No staring at a blank terminal wondering if it hung. The HTML report is a single file. Logos, backgrounds, fonts -- everything is embedded. You can email the report as an attachment and it renders perfectly. It supports dark mode (auto-detects system preference), and all tables are sortable by clicking column headers. Compliance framework mapping. This was the feature that took the most work. The compliance overview shows coverage percentages across all 12 frameworks, with drill-down to individual controls. Each finding links back to its CIS control ID and maps to every applicable framework control. Pass/Fail detail tables. Each security check shows the CIS control reference, what was checked, what the expected value is, what the actual value is, and a clear Pass/Fail/Warning status. Findings include remediation descriptions to help prioritize fixes. Quick start If you want to try it out, it takes about 5 minutes to get running: # Install prerequisites (if you don't have them already) Install-Module Microsoft.Graph, ExchangeOnlineManagement -Scope CurrentUser Clone and run git clone https://github.com/Daren9m/M365-Assess.git cd M365-Assess .\Invoke-M365Assessment.ps1 The interactive wizard walks you through selecting assessment sections, entering your tenant ID, and choosing an authentication method (interactive browser login, certificate-based, or pre-existing connections). Results land in a timestamped folder with all CSVs and the HTML report. Requires PowerShell 7.x and runs on Windows (macOS and Linux are experimental -- I would love help testing those platforms). Cloud support M365 Assess works with: Commercial (global) tenants GCC, GCC High, and DoD environments If you work in government cloud, the tool handles the different endpoint URIs automatically. What is next This is actively maintained and I have a roadmap of improvements: More automated checks -- 140 CIS v6.0.1 controls are tracked in the registry, with 57 automated today. Expanding coverage is the top priority. Remediation commands -- PowerShell snippets and portal steps for each finding, so you can fix issues directly from the report. XLSX compliance matrix -- A spreadsheet export for audit teams who need to work in Excel. Standalone report regeneration -- Re-run the report from existing CSV data without re-assessing the tenant. I would love your feedback I have been building this for my own consulting work, but I think it could be useful to the broader community. If you try it, I would genuinely appreciate hearing: What checks should I prioritize next? Which security controls matter most in your environment? What compliance frameworks are most requested by your clients or auditors? How does the report land with non-technical stakeholders? Is the executive summary useful, or does it need work? macOS/Linux users -- does it run? What breaks? I have tested it on macOS, but not extensively. Bug reports, feature requests, and contributions are all welcome on GitHub. Repository: https://github.com/Daren9m/M365-Assess License: MIT (free for commercial and personal use) Runtime: PowerShell 7.x Thanks for reading. Happy to answer any questions in the comments.
Migration from Hosted Exchange (Hybrid) to M365 Classic Outlook Client Problems and Solutions
Hello Everyone, I'm a tech who started on a 8088 processor in the 80's. Not mentioning the Vic20 and C64 since that hardly seem relevant! I'm posting here to hopefully help the next person with the issues I've had over the last few weeks. My client had to port his email from a provider with an on-perm Exchange server in a Hybrid setup with M365 to his own M365 environment. I expected this was to be about 3 hours of work for me - setup M365 environment, plan the cut-over window, update the Outlook clients on each PC. It ended up being roughly 20 hours of my time and at least 10 hours of dedicated time for my client. For those wanting to jump directly to what mostly fixed it use this link, it should get you past the dreaded "an encrypted connection to your mail server is not available" when trying to add the mail account into a clean profile. Use https://support.microsoft.com/en-us/windows/classic-outlook-troubleshooters-086e3d66-5404-4034-9cc5-545909dcc166 and pick "Classic Outlook Profile Setup Troubleshooter" Most hits are going to tell you its an autodiscovery issue, but if you're reading this I'm going to assume you've already confirmed that. Our issue was some ghost configuration, only on the PCs previously setup for mail on the old server. A new PC could add the same account without issue. Some of the research suggested this would not happen if the proper Microsoft migration process is followed to move the account - but in our case the previous provider was unable to perform the migration. I'll skip over the research we tried along the way, such as New Outlook Profiles, Registry entry changes, MS Personal users with the same email as MS Business Users, Autodiscover problems (including concerns that the base website for the client was offering invalid data), and so on. After each hit where we applied a fix we again had to try adding the mail to the profile, and each time we sat watching the little circle for up to 5 minutes only to get the same error. Now, once we found the link above - which did not come up in most searches - things got better, but not 100%. We added the profile ok but then Outlook gave a permission error while starting. To fix that, the user signed in must have administrative access and you use File Explorer to navigate to the folder identified in the error. In our case it was in folders kept under \Windows\System32\. When prompted that we need to grant permanent access we said yes. In our case this is where Outlook was storing the ost files. That worked for most of the clients, but we had one additional issue where the error was pointing to a folder that didn't exist. Just creating the folder was not enough, the final fix was to hold CTRL-SHIFT down while opening Outlook to start in administrative mode to allow it to create the ost file in the newly created folder. Finally 3 weeks after our cut over window, while the client had to use OWA, we were able to get outlook running. This was critical for my client because they did not have access to the mail history since the migration didn't happen - they had to open a copy of their PST in Outlook and use mail in OWA and constantly bounce back and forth. I hope this helps someone avoid the pain we went though!Sole Microsoft 365 Admin Locked Out After Phone Replacement / Lost MFA Device
I am the sole admin for a Microsoft 365 tenant and I am currently locked out after replacing my phone. The old phone was wiped before Microsoft Authenticator was fully re-registered on the new device. Authenticator was the only MFA method configured on the account. Current situation: password is known, Teams desktop sessions are still active, Authenticator cloud backup restored successfully, but all Microsoft security and admin pages still require approval from the old Authenticator registration. I cannot access Security Info, Entra Admin, or Microsoft 365 Admin Center because every path loops back to the dead MFA registration. I have already attempted Microsoft business support phone lines, Authenticator restore and recovery, and existing desktop sessions, but support queues are disconnecting and I cannot open business support tickets because the admin account itself is MFA locked. Tenant: lowepfg.onmicrosoft.com What is the fastest recovery or escalation path to force MFA reset or re-register Microsoft Authenticator for the tenant admin account?MacOS platform SSO deployment issues
Hello, We tried to deploy MacOS platform SSO but the devices are having problems with their authentication. The devices are connected through company portal but keep asking for logins and authentication, especially on reboot. Some users are prompted to sign-in to their entra account several times per hour. To Deploy it we used the configuration setting template: Authentication > Extensible Single Sign On (SSO) Settings: Extension Identifier: com.microsoft.CompanyPortalMac.ssoextension Authentication Method: Password Token To User Mapping: Account Name: preferred_username Full Name: name Use Shared Device Keys: Disabled Team Identifier: UBXXXXXX Type: Redirect Has anyone here experienced similar issues or found a fix for these constant re-authentication prompts? Thanks!Primer: How to Use RBAC for Applications to Control App Use of the Mail.Send Permission
The temptation to use the Mail.Send application permission in scripts can lead PowerShell developers into trouble because the permission allows access to all mailboxes, including sensitive executive and financial mailboxes. Fortunately, RBAC for Applications allows tenants to control the access that apps have to mailboxes and other Exchange content. All explained here with an example script to test RBAC of Applications. https://office365itpros.com/2026/02/17/mail-send-rbac-for-applications/Does MC1189663 Impact Standard Power Automate Approvals?
Hi everyone After reviewing the change described in MC1189663 (retirement of external access tokens for actionable messages), I'm unsure wheter this also affect the out-of-the-box Standard Approval action in Power Automate. My question is specifically about the default "Start and wait for an approval" / "Standard Approval" action with no special configuration. Does this change impact approval emails or actionable messages generated by the Standard Approval action for internal usage (mails to internal accounts), or will those continue to work without modification? Thanks in advance for any clarification.
