Why is SharePoint Online So Slow? Root Causes & Solutions

Slow SharePoint Online performance is annoying and affects productivity. I’ve troubleshooted these issues across multiple tenants. Now, here I’ll share why is SharePoint Online so slow and how to resolve it.

Let’s understand:

• Why is SharePoint Online Slow to Load & How to Improve it
  • #1. Server Side Latency
  • #2. Unstable Internet Connection
  • #3. SharePoint Throttling
  • #4. Complex Layout and Heavy Web Parts
  • #5. Code Customisations
  • #6. Improper Data Management
  • #7. File Size Versioning
  • #8. Accessing Using Older Browsers
  • #9. External Networks
  • #10. SharePoint Online Storage Quota
  • #11. Device Limitations
  • #12. SharePoint Site Collection Size
• How SharePoint Online Performance is Measured
• Author’s Verdict
• People Also Ask

Why is SharePoint Online Slow to Load & How to Improve it

SharePoint’s performance depends on several factors. Let’s discuss the top reasons and their solutions behind the slow performance of SharePoint Online:

#1. Server Side Latency

Every action performed in SharePoint Online requires the intervention of the server. For instance, loading a page, adding new data, searching, etc. All these requests required time, called the SPRequestDuration. But due to the high number of concurrent users, the server failed to handle all the queries efficiently. As a result, the server gets overloaded with requests that lead to slow performance. Also, large site collections can worsen this; check the site collection administrator in SharePoint Online and regularly audit usage.

Solution

SharePoint Latency is also a key metric that measures the response time of a query. So, to deal with the server-side latency issue to resolve why is SharePoint Online so slow, you can schedule your heavy tasks during off-peak hours. It helps other users to use SharePoint without disruption.

#2. Unstable Internet Connection

Connecting to a stable Internet connection is crucial for a smooth SharePoint experience. If your Internet is not stable or slow, it can also create SharePoint Online slow to load issues while saving or downloading files.

Solution

Make sure you are connected to a stable Internet connection providing sufficient bandwidth. Ensure your Internet bandwidth is in the range of 5-10 Mbps at least.

#3. SharePoint Throttling

To maintain SharePoint’s health, it uses the concept of throttling. This is used to restrict users from uploading large files continuously to SharePoint. It restricts the usage of SharePoint temporarily to prevent overloading. If you are dealing with large data, either uploading or downloading in SharePoint Online, then this might be why SharePoint Online is so slow.

Solution

Avoid the use of SharePoint to perform heavy tasks concurrently. Try to divide them into a specified interval to avoid throttling issues.

#4. Complex Layout and Integration of Heavy Web Parts

Organisations use the customised pages in SharePoint to make them more engaging. But with the integration of heavy web parts and including the customisations, SharePoint Online slow to load. For instance, if the SharePoint page includes several web parts such as high-resolution pages and streaming videos, then it affects the server latency and leads to why is SharePoint Online so slow.

Solution

To get rid of the SharePoint performance issue, try to avoid the use of heavy web parts. Instead of using high-resolution images, use compressed images, and also try to minimise the number of images on a web page. You can also embed the YouTube video link rather than uploading the whole video. Need more clarity? Compare SharePoint Site vs. Page vs. Web Parts to optimise your layout strategy.

#5. Code Customisations

Implementing CSS and JavaScript is a common practice nowadays to make SharePoint’s page more interactive. But they also increase the size of the page, leading to a SharePoint Online slow to load.

Solution

Do not overload the SharePoint page with unwanted CSS and JS. Also, optimised the custom-added CSS and JavaScript files to load them asynchronously so as not to affect the SharePoint performance. You can also refer to Microsoft’s Page Diagnostic tool to filter out the web parts that make the SharePoint page heavier and slow it down.

#6. Improper Data Management

Another main reason for the query Why is SharePoint Online so slow is the inefficient file handling and data management. Adding multiple files in document libraries with poor organisation and excessive versions slows down SharePoint’s speed.

Solution

Make use of OneDrive sync to store the SharePoint files locally. By using the OneDrive sync, users do not need to wait for the loading of SharePoint’s content to access the files. This approach can reduce loading delays, particularly for large files. Additionally, files stored in OneDrive and linked to SharePoint libraries can still be shared and accessed through SharePoint.

#7. File Size Versioning

Users uploading heavy files to the SharePoint storage can also lead to SharePoint Online slow to load. However, storing their versions after the specified changes is also stored in SharePoint and impacts SharePoint loading speed.

Solution

Compressing the files before uploading them to SharePoint easily resolves why is SharePoint Online so slow. Also, limit the number of versions that a SharePoint file should have. It will stop the version policy from creating multiple versions of a file and will not slow down SharePoint.

#8. Accessing SharePoint Using Older Browsers

Using outdated browsers can affect SharePoint Online performance. Microsoft’s SharePoint Online is optimised for the latest technology. Using it in an older browser affects its performance. These browsers cannot render complex pages or run custom scripts efficiently.

Solution

Upgrade to the latest version of the browser. These browsers support the latest web standards and offer better compatibility with SharePoint’s advanced features. Additionally, they also include JavaScript engines and efficient memory management, allowing SharePoint pages to load efficiently. By using an updated browser, users can use SharePoint Online at its best speed.

#9. External Networks

Why is SharePoint Online so slow? Maybe because of external networks. External networks and security configurations can also affect SharePoint Online performance. For instance, VPNs and firewalls add an extra security layer that delays access to SharePoint. It is widely happening with the remote users or those working from different network environments.

Solution

Users can create network exceptions to allow direct access to SharePoint Online without interference from VPNs. By configuring these “split-tunnel” settings for SharePoint Online, users can reduce unnecessary latency while still maintaining network security.

#10. SharePoint Online Storage Quota Exceeded

There might be reasons behind the SharePoint Online slow to load, such as the storage of SharePoint Online. Although Microsoft offers ample storage to store the data in the SharePoint document libraries and lists. But due to excessive use of them, it might get full.

Solution

You can either backup SharePoint Online to local storage or make a replica of your data to another site or tenant. For the same, I suggest opting for the SysTools SharePoint Migration Tool, which can accomplish the process of transferring files to another account in one go. Afterwards, you can remove them and use their storage to save the upcoming files.

#11. Device Limitations

It also matters which device is used to access SharePoint. If the device does not have the essential free storage to run SharePoint smoothly, then you might be puzzled why is SharePoint Online so slow.

Solution

To resolve the device issues, you need to upgrade your system with more RAM or CPU. You can also boost SharePoint performance by closing all the unnecessary apps running in the background. 

#12. SharePoint Site Collection Size

Managing the SharePoint site collection properly is necessary for smooth document management. Having a large number of files in the SharePoint collection can also slow its performance. 

Solution

You can decommission the unnecessary items from the SharePoint site collection. It will free up space in SharePoint and also improve its loading time. If you do not want to remove the items from the SharePoint site collection, then you can archive the data as well. 

How to Measure Performance: Why is SharePoint Online So Slow

Understanding how SharePoint measures performance is critical. It’s not just about page load time.

Key metrics include:

• Time to First Byte (TTFB)
• Page Load Time
• Number of HTTP Requests
• Rendering Time of Web Parts

The Page Diagnostics Tool for SharePoint gives detailed insights into each metric and helps to address SharePoint Online slow to load issues quickly.

Are You Using Classic Sites? That Might Be the Problem

After reading this SharePoint On-Premise vs SharePoint Online guide, I understand that classic SharePoint sites are significantly slower than modern sites because:

• Classic sites rely on older rendering engines
• They’re less optimised for mobile and responsive design
• They often include outdated scripts or unsupported customisations

If you’re using classic sites and experiencing the same issue. Then, it is recommended to migrate from on-premises to SharePoint Online to leverage modern site features.

Performance Impact of Permissions and Sharing Settings

Overcomplicated or broken inheritance structures can slow down library access, item load times, and user asks why is SharePoint Online so slow.

To resolve, follow this:

• Simplify group structures
• Reduce item-level permission customisations
• Use Microsoft 365 groups instead of SharePoint-only groups

How Integrations Can Affect SharePoint Running Speed

I’ve seen SharePoint online slow to load issues caused by third-party extensions integrated into SharePoint. 

Some common slowdowns I observed:

• Apps making frequent API calls
• Inefficient list webhooks or workflows
• Power Automate flows stuck in infinite loops

Audit and disable unused flows, or move heavy logic to Azure Functions when possible.

Should You Use Content Delivery Networks (CDNs)?

If not, then start using CDNs, as they speed up static file delivery, like:

• Logos
• Custom scripts
• CSS files

You can set up Office 365 Public or Private CDNs to offload static assets. 

Pre-Publish Checklist for Preventing Why is SharePoint Online So Slow

Follow this checklist before publishing any SharePoint page:

• Fewer than 5 web parts per section
• Image sizes optimised
• Tested page load using Edge + Page Diagnostics Tool
• Replaced inline code/scripts with SPFx components
• Confirmed permissions aren’t broken or unnecessarily
• Avoided embedding large Power BI dashboards directly

What Helped Me Improve SharePoint Online Speed

After troubleshooting the SharePoint Online slow to load issues, here’s what made a difference in SharePoint Online performance:

• Optimising the homepage with fewer web parts cuts load time by ~40%.
• Switching from images to SVGs or compressed JPGs results in faster rendering.
• Enabling CDN for static assets better the performance for users.
• Using Microsoft’s Performance Toolkit helps to identify slow scripts and poor queries.
• Replacing classic pages with modern, enhances running speed.

Author’s Verdict

Many times, I addressed the query Why is SharePoint Online so slow? That’s why I decided to share my experience with admins like me who are facing SharePoint Online slow to load issues. By using the discussed solutions for every reason, you can fix SharePoint site loading very slow issues quickly.

People Also Ask

Q. Does SharePoint Online have a speed limit?
Not exactly, but document libraries with over 5,000 items or pages with too many scripts or web parts will experience delays.

Q. Will switching to Microsoft Edge improve performance?
Yes, in many cases. Edge is optimised for Microsoft 365, and I’ve seen smoother behaviour with it.

Q. Is SharePoint faster in Teams than in a browser?

No, it uses the same backend. But Teams might feel faster due to its native app interface.

Q. Can Microsoft fix why is SharePoint Online so slow?
No, unless it’s a backend service issue. Most performance problems are caused by design, content, or network mismanagement on the user end.