Portmux is a Google Drive to SharePoint migration service that moves files from My Drives, Shared Drives, and shared-with-me into SharePoint Sites and OneDrive with the permissions, version history, and folder structure your teams depend on.
Google Drive-to-SharePoint is the canonical "we're moving from Google Workspace to Microsoft 365" migration. Files move with content, but Google's permission model (Editor/Commenter/Viewer with link-share) doesn't 1:1 match SharePoint's (Full Control/Edit/Read with sensitivity labels). The hardest decisions are about Shared Drives, each one becomes a SharePoint Site, and the team membership model is fundamentally different.
Personal Drive files migrated to user OneDrive with original folder hierarchy, last-modified timestamp, and ownership preserved.
Each Shared Drive becomes a SharePoint Site with members migrated to the Site's Microsoft 365 Group; folder structure mirrored exactly.
Google Docs converted to .docx with formatting, embedded images, comments, and suggested edits preserved (suggested edits land as Word tracked changes).
Sheets converted to .xlsx with formulas, formatting, sheet structure, conditional formatting, and most charts preserved; some Apps Script automations need re-implementation.
Slides converted to .pptx with layout, themes, embedded media, animations, and speaker notes preserved.
Complete folder hierarchy preserved in SharePoint document libraries; Google Drive labels and starred items mapped to SharePoint columns and tags.
Google Drive permissions (Editor/Commenter/Viewer) translated to SharePoint permission levels (Edit/Read with comment-only via SharePoint check-out) and applied per file/folder.
Google Drive sharing links (Anyone with the link, Specific people) re-created as SharePoint sharing links with equivalent access scope.
Google Drive version history (up to 100 most recent versions per file) migrated as SharePoint Version History with original timestamps and editors.
Google Docs/Sheets/Slides comments migrated as Office Word/Excel/PowerPoint comments with original commenter (matched by email) and timestamp.
Files in Shared with me migrated only if they're also in a Shared Drive; otherwise the original owner's permission grants are recreated post-migration.
Google Drive Labels (Workspace Enterprise only) migrated as SharePoint columns or sensitivity labels; classification taxonomies preserved.
We connect to Google Workspace via a Service Account with domain-wide delegation, which gives us read access to every user's Drive, all Shared Drives, and Drive metadata at scale. Microsoft Graph access is provisioned via a Microsoft 365 application registration with SharePoint and OneDrive write scopes. Within 72 hours you see total file count, total bytes, Shared Drive inventory, and a sharing-link audit.
The mapping decisions are: Shared Drive → SharePoint Site name and Group membership, ownership reassignment for files from departed users, conversion strategy for Google native files (default: convert to Office, keep the Google file as a backup link), and permission-translation rules. Pilot Site provisioned with 1 Shared Drive's content for stakeholder validation before full cutover.
Migration runs in waves: My Drive content first (per-user OneDrive), then Shared Drives (one Site per Drive) prioritized by team. Each wave includes pre-migration communication, in-migration progress dashboards, and a post-migration validation report. After all waves complete, Google Drive is set to read-only for 30 days as a safety net before access is revoked.
Every migration has its own gotchas. Here's what we plan for on this specific path.
Google Drive permissions are simple (Editor/Commenter/Viewer) and inheritable. SharePoint permissions are more granular (Full Control, Design, Edit, Contribute, Read) and inheritance behaves differently. We translate to the closest SharePoint permission level and document where Google's "Commenter" maps to SharePoint Read with sharing on (the closest equivalent).
Files shared with a user that aren't in a Shared Drive are owned by someone else and don't have a clear destination in SharePoint. We catalog these per user and ask the original owner to migrate to a Shared Drive first (so they get a SharePoint Site), or leave them as Google Drive sharing maintained via the original owner.
Apps Script bound to Google Sheets/Docs/Forms doesn't migrate, it's Google-specific JavaScript. We catalog every script in scope and propose Office Script (Excel automation), Power Automate, or Logic Apps replacements during mapping. Most simple scripts re-implement cleanly; complex ones may stay in Google Sheets for that workflow.
Google Workspace gives generous Shared Drive storage; SharePoint has per-Site storage limits and per-tenant Microsoft 365 storage that can be smaller than your current Google footprint. Pre-migration audit identifies orphaned files, departed-user files, and bloated version histories that should be cleaned up before, not after, the move.
Single-system migrations like Google Drive to SharePoint run as Track A engagements: one source, one destination, up to 1M records, 4–6 weeks. Final price depends on object volume, custom field count, and integrations, scoped on a 20-minute call before any commitment. See full pricing →
Tell us what's in the source, where it's going, SaaS or custom, and when you need to be live. You'll walk away with a scoped quote, a named engineer, and a go-live date.