The situation
Meridian Structural Consulting is a 90-person civil and structural engineering firm that moved its project file management to SharePoint Online four years ago. Each active project has its own SharePoint site: drawings, specifications, calculation reports, and correspondence organised into document libraries that the project team accesses daily.
CAD files, especially large .dwg and .rvt files, sit at the heart of this setup. A typical structural drawing might be 30 to 80 MB per file. With multiple engineers revising the same drawings through the week, SharePoint's default version history accumulates fast. The firm had never set a version limit on any library, and the default "keep all versions" behaviour had run unchecked for four years.
Three weeks before their Microsoft 365 renewal, James, the firm's IT administrator, pulled up the SharePoint admin centre storage report. The tenant was at 1.25 TB against a 1.5 TB pool. The storage add-on quote from their Microsoft CSP partner was $0.20 per GB per month - for the 500 GB they expected to need within the next 12 months, that was $1,200 per year, recurring and growing.
What the audit revealed
James used ShareMaster's Report Master to export a per-library storage breakdown across all 34 active project sites. The picture was stark.
| Storage category | Size | % of total |
|---|---|---|
| Live file content (current versions) | 390 GB | 31% |
| Version history (older versions of existing files) | 770 GB | 62% |
| Recycle bin contents | 65 GB | 5% |
| Other (metadata, thumbnails, minor system items) | 25 GB | 2% |
Sixty-two percent of tenant storage was version history. Some drawing libraries carried over 200 versions of a single file from years of incremental revisions. The firm's legitimate requirement: keep the last 20 versions for active projects and the last 5 for archived ones. Everything beyond that was pure overhead.
Why version history accumulates so heavily in engineering environments
Standard office documents (Word, Excel, PowerPoint) are typically 100 KB to a few MB. CAD and BIM files are 30 to 100 times heavier. Version 1 of a structural drawing might be 45 MB; version 87 of the same file adds another 45 MB of version storage. A project site with 120 drawing files, each carrying 80 versions, holds roughly 430 GB of version history before a single live file is counted.
Engineers also save frequently. Many CAD applications are configured to auto-save to SharePoint every 10 to 30 minutes, each auto-save triggering a new version entry. Over a six-month project, that cadence alone can push version counts past 500 for a busy file.
The cleanup plan
James broke the cleanup into three phases to keep risk manageable and avoid disrupting active projects.
| Phase | Scope | Version limit applied | Estimated recovery |
|---|---|---|---|
| Phase 1: Archived projects | 12 sites marked as completed and read-only | Keep 5 versions per file | ~420 GB |
| Phase 2: Active projects (drawing libraries) | Drawing and model libraries across 22 active sites | Keep 20 versions per file | ~320 GB |
| Phase 3: Recycle bin | Tenant-wide recycle bin | Clear items older than 30 days | ~55 GB |
Phase 1: archived project sites
For completed projects, the firm needed only a handful of reference versions: the issued-for-construction drawing, one or two preceding revisions, and the as-built record. James used Space Master's Version Trimmer to process all 12 archived sites in a single batch, setting a 5-version limit per file. The trimmer ran overnight and recovered 420 GB without touching any live project data.
Phase 2: active project drawing libraries
Active projects required a lighter touch. James kept 20 versions to preserve recent revision history while still eliminating the tail of hundreds of auto-save versions. He ran the Version Trimmer against the drawing and model libraries only (not the correspondence or specifications libraries, which were smaller and contained important revision trails). This pass recovered a further 320 GB.
One concern James raised before running Phase 2: would trimming versions affect files currently checked out or actively edited? Space Master skips files with an active checkout lock, so in-progress work was not touched.
Phase 3: recycle bin
Sixty-five GB sat in the tenant recycle bin, including large superseded drawing exports that engineers had deleted months earlier. James used Recycle Master to bulk-clear items older than 30 days across all sites in one operation, rather than navigating to each site's admin bin separately. That step alone freed enough space to push the tenant comfortably back below 50% usage.
The outcome
Total recovered storage: 850 GB across three phases, completed over three days of non-business-hours processing. The tenant went from 1.25 TB to under 400 GB of active usage, well within the base pool.
James set a 20-version library limit on all new project sites going forward using SharePoint's library-level version settings, so the same accumulation cannot repeat. For the archived sites, he set a library-level version cap of 5 at the point of archival. The firm will run a version trim annually as part of its regular IT maintenance cycle.
James cancelled the Microsoft 365 Extra File Storage purchase, eliminating the $1,200 annual renewal cost. The M365 subscription renewed at the same tier.
What to do if your situation looks similar
Before any trimming operation, get the breakdown right. The built-in SharePoint admin centre shows total per-site usage but does not split live content from version history. Without that split, you cannot reliably estimate how much trimming will recover, or which sites to prioritise.
Use Report Master's per-library storage report to get the split first. Then apply the Version Trimmer starting with archived or low-activity sites where the risk of disturbing active work is lowest. Work toward active sites after verifying the first runs produce the expected results.
For storage cleanup guidance that applies beyond version history, the SharePoint storage reduction guide covers the full sequence: version history, recycle bin, image reduction, and bulk file deletion in order of typical impact.