SharePoint Online is one of the more reliable pieces of Microsoft 365, but it has its rough edges. Most of the support tickets we see for it land in five buckets: permission errors, sync issues, slow page loads, broken file access, and confused users.
Here are the five and how we fix them.
1. "Access Denied" errors
The most common SharePoint issue, by a comfortable margin. Usually a permissions problem rather than a real outage.
There are two ways to track it down. If you have a Microsoft 365 admin account, run the Check User Access diagnostic from the Admin Center support pane. It'll tell you exactly what the user can reach, what they can't, and why. For a quick manual check, go into the site itself: Settings → Site permissions → Check permissions, enter the user, and see what's actually assigned.
If permissions look right and the user still can't get in, the fastest fix is usually to remove them from the site entirely and re-add them with the correct permission level. That re-evaluates the inheritance chain and clears most stuck states.
A few permission gotchas worth knowing:
- Permissions can inherit from the site, the library, or the individual file. A "broken" permission is often inherited from somewhere upstream.
- Microsoft 365 group membership and SharePoint site permissions aren't the same thing. Removing someone from a group doesn't always remove their access.
- If conditional access policies are in play, the error might not be a SharePoint permission issue at all. Check sign-in logs in Entra ID.
2. Sync problems with OneDrive
OneDrive does the heavy lifting when SharePoint files sync to a desktop. When sync breaks, the cause is usually one of these:
- Too many files at once. OneDrive starts to struggle past about 300,000 items in a single sync relationship.
-
Unsupported characters in file or folder names.
< > : " / \ | ? *will all break sync, as will leading or trailing spaces. - Files over the size limit. The current cap is 250 GB per file.
- Storage running low. Either on the SharePoint side or on the local disk.
- Old OneDrive client. Sync improvements ship constantly; if it's been a year, update.
For mobile users, mark important files as "Available offline" so they can be opened on the road. A lot of "sync issues" reported from the field are actually files that were never made available offline.
3. Slow page loads
SharePoint pages get sluggish for a few predictable reasons. The fixes are mundane:
- Compress images before uploading. A 6 MB phone photo on a homepage will tank load times.
- Keep web parts in check. A page with twelve highlighted-content web parts will run twelve queries on every page load.
- Use Content Search Web Part (CSWP) instead of Content Query Web Part where you can. CSWP uses the search index and is much faster.
- Trim individual document sizes where possible.
Microsoft's Page Diagnostics for SharePoint tool is worth a look. It runs in the browser, scores the page, and tells you which web parts and assets are slowing things down. Run it before guessing.
4. "View in File Explorer" doesn't work
This one has changed since 2022, and most older articles online are still wrong about it. The classic "View in File Explorer" option relied on Internet Explorer, which Microsoft retired in 2022. It's been replaced with two better options:
- Sync. Click the Sync button in a SharePoint library, and the library appears as a folder in File Explorer via OneDrive. This is now the default way to work with library files like local files.
- Add shortcut to OneDrive. Adds the library as a shortcut inside the user's OneDrive, which then syncs to File Explorer the same way personal OneDrive content does.
If a user is asking how to "open in File Explorer" the old way, the answer is now Sync or Add shortcut to OneDrive. The IE-based workaround isn't worth troubleshooting.
If Sync itself isn't working, the troubleshooting overlaps with #2 above. Start there.
5. The user experience is rough
This one isn't a bug. It's a real complaint that comes up in almost every SharePoint conversation. Out of the box, a default SharePoint site is a confusing mess of generic web parts, vague navigation, and metadata fields nobody filled in.
It's not something you fix; it's something you plan for. A SharePoint rollout that goes well almost always includes:
- Information architecture done before the migration, not after
- Site templates that match how teams actually work
- A short training on the basics (uploading, sharing, version history), with a refresher 30 days later
- An owner per site who knows enough to make small structural changes without filing a ticket
We've seen organizations skip this and then spend the next two years wondering why nobody uses SharePoint. The platform is fine. The rollout is the problem.
When to escalate
Most issues above can be fixed in the admin portal. A few situations are worth opening a Microsoft support ticket for: tenant-wide search failures, persistent sync corruption that doesn't clear after a reset, and any case where Microsoft 365 group membership and SharePoint permissions are visibly out of sync at the directory level.
If you're a TrustedTech customer, those tickets come to us first. We resolve most of them in-house and only escalate to Microsoft when we genuinely need to.
