Google Sheets schema mismatch persists after Regenerate; reverse Ref validation prevents saving an isolated app copy

AppSheet AppSheet Q&A
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Hello AppSheet community,

I’m troubleshooting an undeployed Google Sheets-based app. I created an isolated app copy with both data-copy and file-copy options enabled so I could test without changing the original data.

Table and column names below are anonymized aliases, not the original names.

What I verified:

  • People and FollowUps point to the copied spreadsheet and their correct worksheet tabs.
  • People has 48 populated column headers in row 3. Rows 1 and 2 contain a title and instructions.
  • FollowUps has 27 populated column headers in row 1.
  • People[PersonID] is a Text key.
  • FollowUps[PersonID] is a Ref whose source table is People.
  • The saved copy’s preview reports 48 spreadsheet columns versus 44 schema columns for People, and 27 versus 26 for FollowUps.

What I tried:
I ran Regenerate Structure for People, then FollowUps, in the legacy editor. I also tried regenerating FollowUps in the improved editor.

The attempts resulted in:
“Your changes couldn’t be saved. Please check the app errors highlighted in red.”

The validation errors refer to the reverse-reference virtual column. With names replaced by aliases:

Column Name ‘Related FollowUps’ in Schema ‘People_Schema’ refers to ReferencedTableName ‘FollowUps’. That Table or Slice does not have a valid column structure.

The List column has an invalid expression in its Formula field:
REF_ROWS(“FollowUps”, “PersonID”)
Can’t find table “FollowUps”.

However, FollowUps remains listed in the editor, and its PersonID Ref points to People. The saved preview still reports the original column-count mismatch. I have not verified that any regenerated schema was successfully saved.

I have not deleted the reverse-reference column, removed/re-added tables, reduced spreadsheet columns, or changed security filters to bypass these errors.

Questions:

  1. What should I inspect to determine why regeneration cannot save a valid structure for FollowUps?
  2. Is there a safe recovery sequence for these related tables that preserves keys, Ref relationships, expressions, actions, and security filters?
  3. What additional non-sensitive diagnostics would help distinguish a table configuration issue from a saved-schema/version issue?

I previously submitted Send Feedback and received an on-screen submission confirmation. I do not have an individual support case number. I have not established whether this issue is related to the recent app-definition saving incident.

Thank you for any guidance.

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This sounds like a schema/version issue rather than a problem with the Ref relationship itself. Since the reverse-reference column is showing “Can’t find table” even though FollowUps still exists and points back to People, I’d first verify the saved app definition and table structure before deleting or recreating anything.

I’d recommend backing up the current app definition, checking the exact source worksheet names and column headers, and then testing the tables in a minimal copy. I would avoid deleting the Related FollowUps column or changing security filters until the saved schema is confirmed.

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