When a 12-person services firm migrated 5,000 Notion contacts to a proper CRM, they discovered 30% of their relationship data had simply vanished. Not deleted—flattened. A company could have ten linked contacts, three active deals, and twelve email threads. After export, it became a single contact row with a memo field containing a comma-separated list of names. The linked deals didn't import at all. The email threads disappeared into a text field labeled "notes." What looked like a clean migration was actually silent data rot. Notion's database model is flexible. That flexibility is also its weakness. It stores relationships as linked fields inside Notion, but those links don't survive a CSV or JSON export—they collapse into text, and text is not a relationship. If you're planning to move from Notion to a real CRM, you need to know exactly which nine fields will betray you, why they break, and how to rebuild them before they rot into uselessness. The Nine Fields That Flatten on Export Every field type in Notion either exports cleanly or silently corrupts. Here are the ones that break: 1. Linked Database (Company to Contact) In Notion, you can link a Contact to a Company. That link appears as a pill or tag inside the contact record. On export, it becomes a text field with the company name—and nothing else. You lose the company record ID, the link type, and any reverse relationship. A contact that used to link to "Acme Corp" now has a text value "Acme Corp." If "Acme Corp" has a typo in one record and "Acme Corp." in another, you now have two separate companies. 2. Linked Database (Deal to Contact) Deals in Notion often link to multiple contacts: the primary contact, the champion, the decision maker. These three links are stored as separate linked-field properties. On export, each becomes a comma-separated text string with contact names. There's no way to know which contact was the primary and which was secondary. The deal itself doesn't export at all if it's stored in a separate database—you lose the deal record entirely. 3. Rollup and Aggregation Fields If you have a rollup field that counts linked deals or sums contract value, it exports as a static number—the snapshot value at export time. The formula is gone. If new deals come in before you finish your migration cleanup, those rollups are outdated and you won't know it. 4. Relation Filtering (Reverse Links) A company in Notion might display all linked contacts via a reverse relation. That reverse link is a view, not a stored field—it doesn't export at all. You'll lose the company's contact roster unless you explicitly export the contact database and reconstruct the relationship. 5. Tag Hierarchies (Select with Multiple Levels) If you've used Notion's Select field to create pseudo-hierarchies like "Industry > Tech > SaaS," the export flattens it to a single text value. The structure is lost. In a proper CRM, you can query "all SaaS deals" or "all Tech contacts" because the hierarchy is real. After Notion export, you have text that reads "Tech > SaaS" and no way to filter by it programmatically. 6. Email Thread Links (CRM-to-Email Sync) If you've used Notion's email integration or stored email thread IDs as linked records, they export as text. The actual email threads don't come with them. You lose the message history, attachments, and read/unread status. 7. Activity Timeline (Linked Activities) Activities—calls, meetings, emails—are often stored in a separate Notion table and linked to contacts. On export, you get a text list of activity names or dates, not the activities themselves. The linked activity records don't export unless you export that table separately, and even then, they won't re-link automatically. 8. Status Fields with State Transitions A contact status in Notion might be a Select with six options: "Prospect," "Qualified," "In Negotiation," "Customer," "Churned," "Lost." On export, it becomes plain text. There's no state machine, no history of transitions, no timestamp of when the status changed. You lose the entire audit trail. 9. Formula Fields (Any Calculated Value) If you have a formula field that calculates "days since last contact" or "contract value × renewal probability," it exports as a static number at export time. The formula is gone. If the underlying date or value changes, your exported field stays stale. The core problem: Notion stores relationships in memory and renders them as UI. When you export to CSV or JSON, you export only the snapshots, not the relationships themselves. The Export Formats and What Survives Notion offers three export paths: CSV, JSON, and API. The survival rates differ. CSV Export is the most common and the most lossy. Linked fields become comma-separated text. Dates export as raw timestamps. Numbers lose their formatting. Rich text (bold, links, code blocks) becomes plain text. Attachments are lost. You get one flat table per database—no joins, no hierarchies. JSON Export preserves structure slightly