Light vs Deep Scan

4 min read

SharePoint Storage Explorer offers two scan modes and an additional toggle for file-level version detail. Picking the right combination matters: a deep scan with file-level versions on a 50 TB tenant can run for days, while a light scan often gives you 90% of the answer in an hour.

This guide explains what each option discovers, what it costs in scan time, and the typical use case for each.

The two scan modes

Light scan

A light scan visits each site in the tenant and pulls the metadata SharePoint exposes at the site and library level: site name, library name, total bytes, file count, and library type. It does not enumerate individual files.

Time: minutes to hours, depending on the number of sites. The default scope is the 100 largest sites; the full tenant takes proportionally longer.

Use when:

Setting up the tool for the first time and you want a baseline overview.
Looking for which sites have grown the most — the site-level totals are enough.
Producing a high-level report for management.
You want results today, not tomorrow.

Deep scan

A deep scan visits every file in every library across every selected site. The result is the file-level data behind the top 100 files report, the file-type breakdown, and the per-folder size analysis in the file browser.

Time: hours to days, depending on tenant size and file count. A tenant with millions of files can take many days.

Use when:

You need to identify specific files for cleanup (which 50-MB PowerPoints are still in active sites?).
The file-type breakdown matters (you want to know how much of the tenant is video, PDF, mailbox attachments, etc.).
You are preparing a migration and need precise per-folder sizes.
You have already done a light scan and now need the deeper detail on specific sites.

You can scope a deep scan to a single site or a list of sites — you do not have to deep-scan the whole tenant every time.

The file-level versions toggle

Independent of light vs deep, you choose during first-time configuration whether to scan file-level versions:

Include file-level versions — for every file, the tool enumerates its full version chain (every version SharePoint is retaining). Gives precise per-file version counts and the storage each version chain occupies. Adds substantially to scan time — for some tenants, several days or weeks.
Skip file-level versions — the tool reports only site-level version totals (how much storage versions consume in aggregate for each site). Completes much faster. The aggregate is usually enough to make cleanup decisions; you just do not see which specific files have the largest version chains.

The site-level estimate uses the Storage Used (MB) - File Sizes formula that SharePoint exposes. It is an estimated value, not file-exact, but reliable enough for tenant-level planning.

Recommended sequence

For a new install:

Day 1 — light scan with versions skipped. You get the tenant overview within hours. Decide which sites are worth investigating further.
Day 2 onward — deep scan, scoped to the sites you flagged, still with versions skipped. The top 100 files and file-type breakdown become available for those sites.
Only when you need it — re-run a deep scan with versions enabled, scoped to one or two sites at a time. This is the slowest combination; use it when you have a specific question (e.g. "which files have 500+ versions?") rather than as a routine baseline.

Scan progress and cancellation

The scan runs in the background. The main window shows progress per site (current site, files counted, bytes counted). You can cancel an in-flight scan at any time — partial results are kept for the sites already processed.

If a scan is interrupted (machine reboot, app close), restart the tool and the scan resumes from where it left off rather than starting over.