# A missing Excel source can still leave a convincing number

A native Excel external-link test retained $1,250.25 after its source moved. Inspect the files and learn how to distinguish a cached value from a successful update.

Published 2026-11-15T07:30:00Z by Renaissance Superintelligence Corporation (RSI).

A visible value does not establish that an external workbook link refreshed. We moved a synthetic source workbook, reopened its dependent report without updating links and still saw $1,250.25. An explicit UpdateLink then failed, while the cached value remained unchanged.

## Break one known dependency

We created a small source workbook with Input!A1 set to $1,250.25 and a separate report containing an external reference to that cell. After saving both files, we moved the source to a different filename. Only files created for this experiment were moved.

The report reopened with link updating disabled and displayed the same $1,250.25. Its link inventory still contained one Excel workbook link. The visible answer was consistent with the old source, but the source was no longer available at the referenced path.

We then explicitly requested a link update. Excel raised an UpdateLink error. Reading the report cell again still returned $1,250.25. An acceptance check that looked only for a numeric value would have passed this stale result.

## Inventory links before deciding what a result means

Microsoft documents LinkSources as returning the workbook’s links and UpdateLink as updating specified links. Those operations let the workflow inspect dependencies and attempt the relevant update. Neither the presence of a formula nor its last calculated value establishes when that update succeeded.

For a linked model, record the expected source paths and identify which outputs depend on each source. If an expected workbook is missing or an update fails, stop that delivery path and preserve the evidence. Do not replace the link with its cached number merely to remove the warning.

A link count of zero is a useful check for a deliverable intended to be self-contained. It is not a complete dependency inventory: this experiment covers Excel workbook links, not every query, data connection, add-in or external resource a workbook might use.

Observed missing-source behavior

Step | Report cell | Dependency evidence

Before moving source | $1,250.25 | Source created and saved

Reopen without updating | $1,250.25 | One workbook link

Explicit update attempt | $1,250.25 | UpdateLink raised an error

## Give the reviewer the source relationship

The correct delivery depends on the assignment. A live linked model may need its source workbook and an approved location. A standalone report may need an intentional conversion to values with a dated source record. These are different artifacts; choose the required one before editing the file.

If the task requires a current linked result, make a source update observable. In a test copy, change a known source cell by a known amount, update the link and confirm the dependent result. Keep the original source unchanged. This is the same reasoning as our Power Query witness, applied to a different dependency.

Retain both the failing link and the error record when diagnosing a production issue. A screenshot of a plausible number cannot distinguish the successful refresh from the failure we observed. The formula, source identity and update outcome are what explain it.

## Recreate the broken path in a new directory

Download the [linked report](/research/native-office-2026-11-15/linked-report.xlsx), [deliberately moved source](/research/native-office-2026-11-15/link-source-deliberately-moved.xlsx), [exact result](/research/native-office-2026-11-15/external-link.json) and [experiment script](/research/native-office-2026-11-15/native-external-link.ps1). The script creates fresh files under the supplied directory and deliberately moves its own source. Run it only in a new task directory.

The published report retains the experimental link and its cached result; it is failure evidence. Its embedded original task path will not be your local path. Use the script to reproduce the relationship rather than treating the downloaded link as a portable working model.

Use [Panes desktop execution](/docs#commands), then apply the [workbook acceptance checks](/blog/verify-ai-generated-excel-workbooks). For query-backed workbooks, read the separate [RefreshAll failure test](/blog/excel-refreshall-stale-data); the visible symptom can be similar while the dependency and corrective action differ.

## Evidence

Prepared scripted execution on one retained 4-vCPU, 16-GB Windows research computer, November 15, 2026. Excel 16.0 build 20527. The native script reached its result in 1.769 seconds before finally-block cleanup; API time was 2.219 seconds and controller wall time 2.302 seconds. The result is OBSERVED-CACHED-VALUE, not an accepted refreshed report. The task-specific path in the published formula is replaced with $TASK_DIR. One observed run, not an autonomous-agent or fleet benchmark. Per-task operating cost is unmeasured. Public Office copies have author metadata redacted; all other ZIP members are identical to the native outputs. They were reopened read-only in Office without changing their bytes.

## Sources

- [Microsoft: Workbook.LinkSources](https://learn.microsoft.com/en-us/office/vba/api/excel.workbook.linksources)

- [Microsoft: Workbook.UpdateLink](https://learn.microsoft.com/en-us/office/vba/api/excel.workbook.updatelink)

- [Exact native result](https://usepanes.com/research/native-office-2026-11-15/external-link.json)

- [Public-file identity and native reopen](https://usepanes.com/research/native-office-2026-11-15/publication-manifest.json)