I'm trying to import an 8k+ leads list, but only ~3700 go thru. Anyone know how to fix this?

It is updating some existing leads, but at least half the list is new users that haven't been added to intercom.

If some users don't have user_id, they won't be added?

50% of the list are non existent, but did not contain user_id.

Is this reason? Do i need to attach user_id to each import?

This is almost certainly a deduplication issue rather than a hard import limit. When Intercom processes a CSV without a user_id column, it uses email as the unique identifier. 

If an incoming email already exists in your workspace as a lead or user, Intercom updates that record rather than creating a new one, so your "added" count reflects only net-new contacts, not the full list. The missing ~4,300 were likely already in your workspace and got silently updated instead.

The fix is to include a user_id for each row so Intercom can distinguish records more precisely. If you use a third-party tool like Data Migration, it only moves missing leads, but no duplicates.

Hi ​@Zee, Seán here from the Fin technical support team 👋

Racheal is right that some of these imports may be updating existing records instead of creating brand new leads. When you import via CSV, Intercom can identify contacts by either user_id or email, and if both are present, user_id takes priority.

So to answer your question directly: no, a lead does not need a user_id in order to be imported, as long as it has an email address.

If the email in your CSV already exists in Intercom, the import may update that existing record instead of creating a new one.

A couple of things to be aware of:

• If you’re importing leads and the email matches an existing user, Intercom will update that user instead of creating a new lead.
• Using user_id is recommended for consistency, but it’s only required if there’s no email in the row.

You can read more here:

• Import your user data into Intercom
• Merge lead and user profiles

If you’re still seeing genuinely new email addresses not appear after the import, that would be worth investigating more closely, as it may point to row-level import issues rather than the lack of user_id alone.