If you’re running out of SharePoint storage, you’re not alone. Storage usage grows faster than most admins expect.
SharePoint is the underlying engine behind Teams files, OneDrive, Microsoft 365 Groups, Viva Engage, and Power Platform solutions - so when your storage tiers suddenly creep into the red, it’s usually SharePoint that’s taking the punch.
But here’s the good news: not all storage optimization requires complicated changes, governance revamps, or user disruption. In fact, one of the fastest, most impactful, and lowest‑effort ways to free up huge amounts of SharePoint storage is simply to identify and archive (or delete) inactive sites.
This isn’t a theoretical win. For most organisations we work with, more than ~20% of all sites have not been touched in 6–12 months - yet they collectively consume massive amounts of storage.
In this guide, we unpack why inactive sites are the easiest storage win in SharePoint, how to find them using the built‑in admin tools, and how SProbot helps you to more easily and conclusively identify them.
Why inactive sites consume so much SharePoint storage
Inactive sites are often among the largest because they typically belong to long‑completed projects, legacy teams, or initiatives that ran for years but then stopped suddenly. They often contain:
- Years of files
- Media, PDFs, and design assets
- Backups and zip archives
- Old versions of documents
Inactive sites are also most often unmanaged (and not actively reviewed for relevance), so they quietly sit in the background consuming storage.
Why admins often overlook inactive sites
Most SharePoint admins know they exist, but:
- There’s no simple built‑in report listing inactive sites vs storage usage.
- Teams sprawl makes site ownership unclear.
- Manually checking activity logs for dozens or hundreds of sites is time‑consuming.
- Admin centers require multiple clicks per site to inspect usage and lifecycle state.
The ROI of cleaning up inactive SharePoint sites
Cleaning up inactive sites yields three key benefits:
You immediately free storage capacity
Because inactive sites are often heavy, archiving or deleting just a handful can free tens or hundreds of gigabytes.
Your security posture improves
Inactive sites also contain:
- Stale permissions
- Old internal or external sharing links
- Sensitive data that nobody is monitoring
Cleaning them up reduces risk surface area.
SharePoint search, navigation, and indexing improve
A leaner tenant means:
- Faster content searches
- Fewer irrelevant results
- Better overall user experience
How does Microsoft 365 archive work?
Read our overview of how the integrated archiving functionality of Microsoft 365 archive works.
How to find and manage inactive sites using the SharePoint Admin Center
The SharePoint Admin Center does provide tools to find large sites, view last activity dates, and evaluate whether a site is still in use. The process is usable if your tenant is small or if you’re doing a once‑off cleanup.
Step 1 — Open the SharePoint Admin Center
You'll by default see the Active sites list.
Step 2 - Sort by Last activity
Use the Last activity field to sort from older to newer, or filter by Older than 30 days, Older than 90 days, or Never had activity to find candidates for action.
Step 3 - Review storage
With the results returned, look at the Storage used (GB) column to see how much storage is consumed by sites returned first in the old to new sort or filter sequence.
Step 4 - Determine candidates for archiving
Sites with high storage consumption but last activity older than 1 or 2 years are prime candidates for archiving or removal.
To improve sorting, filtering and general analysis capability, select the fields you want to review and then export to CSV to enable further processing in Excel.
These are the properties you might look at when deciding whether to archive or delete:
- Owners and members
- Number of files
- Files viewed or edited
- Page views
- Page visits
Step 5 - Archive or delete
If you have configured Microsoft 365 Archive, the Archive button is available on individual or multiple sites.
How to find and manage inactive sites using SProbot
In Reports > Reviews, choose the Inactive workspaces review.
You can use the Sites with last activity dropdown to filter to an inactivity period.
When you identify a site which isn't relevant anymore, you can use the actions toolbar to archive or delete it.
You can also configure ongoing automatic cleanup to prevent having to manually check for inactivity every few months.
This enables you to specify a threshold for inactivity, send archival notifications and reminders, and automatically archive sites if owners do not respond.
What about active sites with inactive files?
SProbot enables you to find sites with a recent Last activity timestamp, but a high percentage of inactive files.
Read more about how you can use the Sites with many inactive files review to track down these sites.
