Teams signing you out constantly — every morning, several times a week, or mid-session — is almost always a token or credential problem rather than something wrong with Teams itself. The app is functioning; it’s the authentication layer underneath it that’s being interrupted. For a broader walkthrough, our Complete Guide to Fixing Windows, Browser, and Software Errors is a good next read.
Before doing anything: which account is involved? Personal Microsoft account or a work/school Microsoft 365 account? The causes are different. Work accounts are controlled by IT policies and the organisation’s Azure AD settings. Personal accounts are more straightforward. This matters because some fixes only apply to one type.
The immediate quick check — Windows account connection
Settings → Accounts → Access work or school. Does your work account show there? Is there any sync error or warning on it? Teams uses this Windows-level connection for its authentication token. If the Windows account connection has expired or shows an error, Teams inherits that problem.
Click on the account → Info → Sync → if there’s an error, it surfaces here. Sometimes the fix is as simple as clicking “Sync” and re-entering credentials at this level, after which Teams stops asking.
Modern authentication and legacy settings
Teams uses OAuth 2.0 / Modern Authentication. If the tenant’s IT has Modern Authentication disabled (older Microsoft 365 configurations), Teams falls back to basic auth, which is less stable and gets signed out more frequently when tokens expire.
Users can’t check this themselves — it’s a tenant-level setting. If IT recently made changes to authentication settings and sign-outs started happening around the same time: that’s the conversation to have with IT.
Clear the credentials that Teams is trying to use
Windows Credential Manager stores Teams authentication tokens. When they become stale — password changed, account security update, MFA re-enrollment — Teams keeps trying to use the old token, fails, and signs out.
Search “Credential Manager” in Start → Windows Credentials tab → look for entries containing “MicrosoftTeams,” “msteams,” “Office,” or “MSTeams” → remove them. After removing, restart Teams and sign in fresh. This creates a new credential entry rather than trying to reuse the expired one.
Worth doing this before reinstalling Teams — it fixes the sign-out loop about half the time and takes two minutes.
New Teams vs Classic Teams
Microsoft migrated most users from Classic Teams (1.x) to New Teams (2.x) starting in 2023. Authentication handling changed significantly between versions. If Classic Teams was stable and New Teams keeps signing out: the authentication token storage location moved and the new version may have issues importing the existing session.
Check which version is running: Teams → three-dot menu → Settings → About Teams → version shows at the top. New Teams shows version 2.x. Try switching: within Teams → three-dot menu → try “Switch to classic Teams” if available. If Classic Teams is more stable for authentication, use it while waiting for the New Teams authentication issues to be patched.
Conditional Access policies
On corporate accounts: IT can configure Conditional Access policies in Azure AD that require devices to meet certain conditions to maintain a Teams session. When a device falls out of compliance — antivirus disabled, Windows Update not applied, machine not enrolled in Intune — the session is terminated and Teams signs out.
Signs this is the cause: happens specifically after you skipped a Windows update, after an antivirus scan lapsed, or after the machine was offline for an extended period. Settings → Accounts → Access work or school → click the account → Info → look for any compliance errors. If there’s a compliance issue listed: resolving it (install the update, re-enable antivirus, reconnect to VPN for Intune sync) should stop the sign-outs.
Teams cache clearing
New Teams stores its application data in: %localappdata%PackagesMSTeams_8wekyb3d8bbweLocalCacheMicrosoftMSTeams
Classic Teams: %appdata%MicrosoftTeams
Quit Teams completely (system tray → right-click → Quit). Delete the Cache, Code Cache, and GPUCache folders inside the Teams data directory. Don’t delete the entire directory — just the cache folders. Restart Teams. After cache clearing, Teams rebuilds its local state and re-authenticates cleanly, which often resolves persistent sign-out loops caused by corrupted cached tokens.
Multiple accounts and session conflicts
If you’re signed into Teams with both a personal Microsoft account and a work account, or signed into multiple work tenants, authentication conflicts can cause one account’s session to interfere with another’s. Teams handles multi-account scenarios better in the newer versions, but edge cases still cause unexpected sign-outs.
Simplify: sign out of all accounts in Teams → restart → sign into only the primary account → test stability for a day. If sign-outs stop with a single account and return when adding the second, the conflict is between the two accounts’ authentication sessions.
Microsoft 365 session policy — the token lifetime
IT administrators can set the access token lifetime for Microsoft 365 apps including Teams. A short token lifetime (1–4 hours) means Teams re-authenticates frequently. If the re-authentication prompt isn’t visible (because Teams is backgrounded or on a locked screen) and silent re-authentication fails, Teams signs out.
This is policy-controlled and not user-fixable. But knowing it’s the cause helps: if sign-outs happen at regular predictable intervals (e.g., every 4 hours or every 8 hours), that’s a strong indicator of a token lifetime policy. Tell IT the pattern — they can review the token lifetime settings and potentially increase them, or enable persistent refresh tokens that survive session interruptions.
For the underlying account and credential issues, the Teams not working guide covers the connectivity and performance problems that sometimes accompany authentication failures. The Windows account connection issues here overlap with OneDrive sign-in failures — both draw from the same Azure AD token infrastructure. Microsoft’s Teams sign-in troubleshooting covers the detailed diagnostic steps for enterprise tenants including the Teams client debug logs that Microsoft support uses for persistent authentication failures.
Network interruptions and silent sign-out
Brief network drops — the kind that last 5–10 seconds and are barely noticeable — can interrupt Teams’ token refresh process at exactly the wrong moment. If the refresh fails, the session becomes invalid and Teams signs out. You didn’t notice the network blip, but Teams did.
Check: does this happen more when working on Wi-Fi than ethernet? Teams is more sensitive to brief interruptions than most applications because its authentication tokens have strict timing requirements. If sign-outs correlate with being on Wi-Fi (especially in areas with variable signal), switching to a wired connection or fixing the Wi-Fi stability first might resolve the Teams sign-outs as a side effect.
Windows Hello and certificate expiry
On corporate Windows 11 devices using Windows Hello for Business, a device certificate is part of the authentication chain. When this certificate expires — typically annually — authentication to Azure AD services including Teams fails, causing sign-outs.
The certificate expiry happens quietly in the background. Users notice it as Teams suddenly starting to sign out after months of stability. Settings → Accounts → Access work or school → your work account → Info → Device sync status. Any certificate error shows there. The fix is IT-side: they need to renew the device certificate through their certificate management infrastructure. Users can’t renew device certificates themselves on managed corporate machines.
Azure AD Primary Refresh Token issues
Windows 11 uses a Primary Refresh Token (PRT) as the master authentication token for Azure AD-integrated apps. Teams is one of them. If the PRT is invalid or can’t be refreshed — typically due to a clock skew (system clock wrong), domain trust issue, or Azure AD connectivity problem — all Azure AD apps including Teams sign out, often simultaneously.
Check whether Outlook, OneDrive, and Teams all started having authentication issues at the same time. If they did, the PRT is the common element. Verify the system clock is correct (right-click taskbar clock → Adjust date and time → Sync now). An incorrect system clock causes PRT validation failures because tokens are time-stamped.
If the clock is correct and all Microsoft apps are losing sessions simultaneously: the device may have lost trust with Azure AD. Settings → Accounts → Access work or school → disconnect the work account → rejoin (this re-establishes the device registration with Azure AD and generates a fresh PRT). Note: this typically requires IT credentials or IT involvement to rejoin on managed devices.
Teams running out of allowed sessions
Microsoft 365 limits the number of active sessions per account. For most plans, this is up to 15 simultaneous sessions across devices. If a user has many devices where Teams is signed in — old laptops, tablets, phones, shared computers — the session limit can be hit, causing the oldest sessions to be terminated.
Check active sessions: account.microsoft.com → Security → Sign-in activity or Devices. Remove sign-in from devices you no longer use. Alternatively, visit myaccount.microsoft.com → Security → Manage your sessions → sign out of all devices → sign in fresh on the devices you’re actively using. This clears the session accumulation without changing any settings.
Teams background app permissions
If Teams is configured as a startup app but Windows terminates background apps aggressively to save memory, Teams may lose its background process — and with it, the ability to silently refresh authentication tokens. The next time Teams tries to send a notification or sync calendar, it finds its session expired.
Settings → Apps → Installed apps → Teams → Advanced options → Background apps permissions → “Always.” This prevents Windows from terminating the Teams background process. Also check: Settings → System → Power → Energy recommendations — some power-saving modes limit background app activity in ways that interfere with authentication refresh.
Time zone and regional settings
Teams authentication tokens are tied to time stamps. If the system time zone is set incorrectly — even if the displayed time looks right — the underlying UTC calculations may be off. Azure AD validates tokens against UTC time, and a time zone configuration error can cause tokens to appear expired before they actually are.
Settings → Time and language → Date and time → confirm both the time zone and the current time shown are accurate. Set time automatically → Sync now. This is a quick thing to verify and eliminates a subtle but real authentication failure mode.
Teams for personal use vs work account
Microsoft Teams has two distinct versions: Teams for personal use (free, Microsoft account) and Teams for work or school (Microsoft 365, Azure AD account). If the wrong Teams application is installed for the account type, authentication behaves unpredictably. Teams for personal use can’t authenticate work/school accounts properly, and the work version handles personal accounts differently.
Check: download page teams.microsoft.com shows options for “for work and school” or “for personal use.” Ensure the installed version matches the account type. The Microsoft Store version of Teams handles both account types in New Teams, but may still show authentication issues if the account type is ambiguous during the initial setup.
Reinstalling Teams cleanly
When all the above steps haven’t resolved persistent sign-outs: a clean reinstall removes cached authentication state that can’t be cleared through the app itself.
- Sign out of Teams explicitly before uninstalling
- Quit Teams (system tray → Quit)
- Settings → Apps → Teams → Uninstall
- Delete
%localappdata%PackagesMSTeams_8wekyb3d8bbwe(New Teams) or%appdata%MicrosoftTeams(Classic Teams) - Delete Teams entries from Credential Manager
- Restart the PC
- Download and install Teams fresh from teams.microsoft.com
- Sign in and observe over the following days
This process is thorough enough that if it doesn’t resolve persistent sign-outs, the issue is infrastructure-side — Microsoft’s authentication servers, the organisation’s Azure AD configuration, or the device’s domain trust status — rather than something fixable locally.
One pattern that’s worth flagging because it catches people out: sign-outs that happen specifically on Monday mornings. This is often the session lifetime — tokens valid for 72 hours expire over the weekend when Teams was closed, and Monday morning’s first open triggers a full re-authentication rather than a silent token refresh. The fix is keeping Teams running in the background (or the system running in sleep rather than shut down) over weekends, or ensuring the background process has permission to refresh tokens silently while the machine is idle. Not glamorous, but it explains a frustratingly regular pattern.
And if sign-outs are happening to the entire team simultaneously rather than just one person: that’s definitively a server-side issue — a Microsoft service disruption or a tenant-level policy change. Check status.microsoft365.com for any Teams authentication incidents. If there’s an ongoing incident, local troubleshooting won’t help. Wait for Microsoft’s resolution, which typically comes within hours for authentication-affecting incidents given how widespread the impact is.
Documenting the exact sign-out pattern before contacting IT or Microsoft support saves significant time. Note: time of day when sign-outs happen, whether they’re silent (you notice later) or explicit (Teams shows a sign-in prompt), which account is affected, whether other Microsoft 365 apps sign out at the same time, and whether it happens on specific networks (VPN, office, home). This information is what support engineers ask for in their first troubleshooting question, and having it ready moves the conversation directly to solutions. If this sounds familiar, Internet Keeps Cutting Out is worth a look.
