QuickBooks Desktop Sync Issue: Invalid String. The String may contain unsupported or illegal chars

An object you are trying to sync to QuickBooks Desktop contains a field with one or more characters that QuickBooks Desktop does not support. QuickBooks Desktop rejects the record with this error:

Example: Invalid String. The String may contain unsupported or illegal chars.

Why QuickBooks Desktop rejects the record

This error message comes directly from QuickBooks Desktop's own SDK, not from Maxio. When QuickBooks Desktop's SDK rejects a record during sync, it returns this text as-is, and Maxio logs and stores that message exactly as received, without parsing or rewriting it. That is why the message reads as a raw QuickBooks Desktop SDK error rather than a Maxio-style validation message.

The underlying cause is a field on the record being synced that contains one or more characters QuickBooks Desktop's SDK does not support. This is typically caused by copying and pasting content into the problem field, since pasted text can carry along characters that look normal but are not valid in QuickBooks Desktop's supported character set. Exactly which characters QuickBooks Desktop's SDK rejects, and why, is a detail of QuickBooks Desktop itself and is not something Maxio's codebase determines.

Retype the field to remove the invalid character

QuickBooks Desktop's error does not identify which record or field contains the invalid character, only that one exists somewhere in the object being synced. Once you find the field, correcting it requires retyping it manually, since copying and pasting the existing text again would carry the invalid character forward too.

To remove the invalid character

1. Open the record named in the sync error and review its text fields for anything that was copied and pasted from another application.
2. Delete the text in the field that contains the unsupported character.
3. Manually type the same text back into the field, then save the record.
4. Sync again. The record should now sync to QuickBooks Desktop.

Prevent unsupported characters from syncing

Type text directly into Maxio fields instead of copying and pasting it from another application, since pasted text is the typical source of characters QuickBooks Desktop's SDK does not support.

Related information

Maxio also automatically replaces certain invalid characters instead of blocking the sync entirely, which is a related but distinct behavior covered in Customers, Contracts, or Invoices with Replaced Invalid Characters.