Troubleshooting
apt / dpkg: “Could not get lock /var/lib/dpkg/lock-frontend” on Ubuntu and Debian
Last Updated: October 4, 2026apt install or apt update stops with "Could not get lock /var/lib/dpkg/lock-frontend". Another package tool is running. The lock is released by itself when that process ends, so the fix is to find the holder and wait for it, not to delete lock files. Here is how to identify it, when it is safe to stop it, and how to repair a crash.
“The trust relationship between this workstation and the primary domain failed”
Last Updated: October 4, 2026A domain-joined PC refuses domain sign-in with "The trust relationship between this workstation and the primary domain failed". The computer account password no longer matches the one in Active Directory. Here is how to prove that, find out why, and repair the secure channel without deleting the computer account or rejoining the domain.
Entra ID error AADSTS50020: “User account from identity provider does not exist in tenant”
Last Updated: October 4, 2026You sign in to a Microsoft 365 or Entra app and get AADSTS50020. It means the account you used is not a member or invited guest of the organisation you are trying to enter. Here is how to read the message, fix the common cases for the user, and what the admin of the organisation needs to check.
Group Policy Event ID 1053 / 1055: “Windows could not resolve the user name” (name resolution failure)
Last Updated: October 4, 2026gpupdate fails and the System log shows GroupPolicy Event ID 1053 or 1055. The PC could not resolve a name to find or use a domain controller, which is almost always a DNS problem on the client, not a broken policy. Here is how to read the error code, prove the DNS fault, and fix it.
Blue screen INACCESSIBLE_BOOT_DEVICE (stop code 0x7B): Windows cannot reach its own disk
Last Updated: October 4, 2026The PC restarts into a blue screen saying INACCESSIBLE_BOOT_DEVICE, often right after a firmware change, a disk clone or a failed update. Windows has lost the path to its own system disk. Here is how to check the non-destructive causes first (storage mode, recent updates, boot files, storage drivers) and what to have ready before you change anything.
Kerberos clock skew: “There is a time and/or date difference between the client and server” (KRB_AP_ERR_SKEW)
Last Updated: October 4, 2026Domain sign-in, file shares or replication fail because a clock is more than 5 minutes away from the domain controller. Here is how to measure the offset, find out which clock is wrong and why, fix the time source properly, and stop a hypervisor from putting the wrong time back.
New Microsoft Teams shows a blank window or loads forever: how to fix it
Last Updated: October 4, 2026The new Microsoft Teams app opens to a white or black window, or spins on a loading screen, and never reaches your chats. Diagnose it first: check the web version, quit Teams properly, look at WebView2 and your security software, then repair, clear the cache and reset, in that order. Classic Teams (%appdata%\Microsoft\Teams) has been retired and is not the place to look.
OneDrive stuck on “Processing changes” for hours
Last Updated: October 4, 2026The OneDrive icon says "Processing changes" and never finishes. Most of the time the sync app is busy with a very large number of files, or it is stuck on one file it cannot sync. Here is how to find the cause and fix it, starting with the least disruptive step and ending with a reset that does not delete your files.
Outlook error 0x800CCC0E: “Cannot connect to the server” on an IMAP account
Last Updated: October 4, 2026Classic Outlook stops syncing an IMAP account and reports error 0x800CCC0E, "Cannot connect to the server". The error only says Outlook could not reach or sign in to the mail server. Here is how to tell a Microsoft-documented Gmail or Yahoo sign-in problem from a wrong port, a blocked port or antivirus mail scanning, with the least invasive fix first.
Classic Outlook stuck on “Loading Profile”: how to get it open without losing mail
Last Updated: October 4, 2026Classic Outlook for Windows sits on the "Loading Profile" splash screen and never opens. Work through the causes from least to most destructive: stuck processes, a pending Windows update, safe mode and add-ins, the profile and data files, a repair, and only then a rebuilt OST or a new profile. Includes what never to delete.
PowerShell: “running scripts is disabled on this system” (execution policy)
Last Updated: October 4, 2026A .ps1 file will not run and PowerShell says running scripts is disabled on this system. That is the execution policy, which is Restricted by default on Windows 10 and 11. Here is how to read the policy scopes, pick the narrowest fix (one run, your user, or the machine), deal with downloaded files and Group Policy, and why this is a safety rail, not a security boundary.
Print Spooler keeps stopping: “The RPC server is unavailable” (0x000006ba)
Last Updated: October 4, 2026Printing fails with error 0x000006ba, "The RPC server is unavailable", or the Print Spooler service stops again and again. The error code has several causes. This article starts with finding out which one you have, then clears the queue and removes the driver that is crashing the spooler.
SSH: “WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!” and “Host key verification failed”
Last Updated: October 4, 2026ssh refuses to connect because the server's host key no longer matches the one saved in known_hosts. Sometimes that is harmless (the server was rebuilt), sometimes it is not. Here is how to tell which, how to remove only the stale entry with ssh-keygen -R (including non-standard ports and hashed files), and how to check the new fingerprint before you trust it.
Wi-Fi says “No internet, secured”: connected to the router but nothing loads
Last Updated: October 4, 2026Windows shows your Wi-Fi as "Connected, secured" but with "No internet". The radio link is fine; something after it is not. This article finds which of five things it is (no address from DHCP, no gateway, DNS failure, a captive portal, or a VPN driver in the way) and fixes it from the least disruptive step to the most.
Windows Update error 0x80070002 or 0x80070003: update fails or will not install
Last Updated: October 4, 2026A cumulative update downloads, then fails or rolls back with 0x80070002 (file not found) or 0x80070003 (path not found). The cause is usually a damaged Windows Update download cache or a damaged component store. Here is how to read the logs, reset the update cache without deleting anything, and repair the component store in the right order.
Failed to mount /dev/mapper/root on real root: fixing btrfs “parent transid verify failed”
Last Updated: September 26, 2026Your Linux machine unlocks the disk, then drops to a [rootfs ~]# emergency shell because the btrfs root will not mount. Here is how to read "parent transid verify failed", restore the good superblock copy without making things worse, and stop a host restart from doing it again.
Office 365 sign-in: “Oops, something went wrong”
Last Updated: September 21, 2026You sign in to activate Office or set up Outlook, and right after the password the window says "Something went wrong", often with a code such as 1001 or CAA50021. The cause is almost always the Windows sign-in broker or the device's Entra ID registration. Here is how to tell which, and how to fix each.
Edge error 1714 / 1612: “The older version of Microsoft Edge cannot be removed”
Last Updated: September 21, 2026Every time Edge updates, the Application log fills with MsiInstaller Event ID 11714: error 1714, system error 1612. Edge itself is fine. The cause is an orphaned Windows Installer registration left behind by an old MSI install of Edge. Here is how to find it, prove it is orphaned, and remove it safely.