When you use Outlook with a Microsoft 365, Exchange, or Outlook.com account in Cached Exchange Mode, the entire mailbox including every subfolder is downloaded to your local hard drive. Over time, large folders like Sent Items, Archive, or old project folders can consume tens of gigabytes of disk space. This article explains how to configure … Read more
When you use Microsoft 365 Groups in Outlook, new messages often appear slowly or not at all in the Groups pane. This sync lag happens because Outlook uses a cached copy of group conversations that updates on a timer, not in real time. The problem is most noticeable after you send a reply or receive … Read more
If you need to look up coworkers or contacts from your company’s LDAP directory directly inside Outlook but your organization does not use Microsoft Exchange, you can configure Outlook to query the LDAP server directly. LDAP is the standard protocol that directory services such as Active Directory, OpenLDAP, or FreeIPA use to store user and … Read more
When you use Outlook AutoArchive to move old emails to a local PST file while also having an Online Archive mailbox from Microsoft 365, you may see duplicate items, missing emails, or error messages about sync conflicts. This happens because both features try to manage the same messages using different storage rules. This article explains … Read more
When Outlook fails to sync specific folders, you may see stale data or missing emails in one folder while others update normally. The cause is often a corrupted synchronization state or a folder-level sync failure that Outlook does not clearly report. This article shows how to use MFCMapi, a free Microsoft tool, to inspect the … Read more
If you store an Outlook PST data file in OneDrive, you may see sync errors, file corruption warnings, or Outlook failing to open. OneDrive constantly syncs the PST file to the cloud, and because Outlook locks the file during use, the sync fails and produces errors like “We can’t sync this file” or “Something went … Read more
When you mark an email as read on your Windows PC, you expect it to show as read on your iPhone or Android phone. But sometimes the read status does not sync, leaving you to re-read messages on each device. This problem usually happens because the email account is not configured to use Exchange ActiveSync … Read more
When you assign a category in Outlook on the web and then open the same item in the desktop version of Outlook, the category color may appear different or completely wrong. This mismatch happens because Outlook on the web and Outlook desktop use separate category storage systems that can fall out of sync. This article … Read more
Outlook add-ins can slow down the application and cause delays when you start the program or switch between views. The Slow and Disabled Add-ins report in Outlook shows which add-ins take the longest to load and which ones have been automatically disabled due to performance problems. This article explains how to open the report, interpret … Read more
When Outlook takes too long to start, finding the root cause can feel like guessing in the dark. The problem is often a slow add-in, a corrupt profile, or a network timeout during the initial connection. This article explains how to enable trace logging in Outlook to capture a detailed startup profile, then shows you … Read more