#BUSY! flashing in excel every time a function is invoked

[mwilk-drw]

Expected behavior

I expect to not see the #BUSY! error every time a function is invoked with a changing input. I'd like to either see the previous value until a recalculation completed or the new value to be returned quickly enough that it's not as noticeable.

Current behavior

Every time a function is recalculated with a new input, #BUSY! is flashing across all the values. This makes the custom functions unusable with inputs that change frequently.

See attached clip for a demonstration: https://github.com/user-attachments/assets/139e12b0-d048-487c-a704-fcb979bc224d

Steps to Reproduce

Create a spreadsheet with a changing value (eg. the increment function from the sample project), and pass this value in to a custom function implemented in typescript, either the existing add function or something even simpler. Eg.

/**
 * Echoes a number.
 * @customfunction
 * @param first The number to echo.
 * @returns The number.
 */
export function echo(first: number): number {
  return first;
}

Invoked in the spreadsheet with a cell reference of the increment: =UPXL.ECHO(B3)

Context

• Operating System: Windows 10 Enterprise 22H2 build 19045.5487
• Node version: v22.14.0
• Office version: MS Office LTSC Professional Plus 2021
• Tool version: Excel Version 2108
• "generator-office": "version": "3.0.1"
• "yo": "version": "5.1.0"

Failure Logs

No errors in the OfficeAddins.log.txt:

3/13/2025 13:24:00 Medium CustomFunctions [Execution] [Async] [End] [Success] Function=ECHO, Workbook=Excel add-in 407248da-0b4e-4409-aa2f-ed4d328610af.xlsx 3/13/2025 13:24:00 Medium CustomFunctions [Execution] [Async] [End] [Success] Function=INCREMENT, Workbook=Excel add-in 407248da-0b4e-4409-aa2f-ed4d328610af.xlsx 3/13/2025 13:24:00 Verbose CustomFunctions [Execution] [Async] [Begin] Function=UPXL.ECHO, Workbook=Excel add-in 407248da-0b4e-4409-aa2f-ed4d328610af.xlsx 3/13/2025 13:24:00 Medium CustomFunctions [Execution] [Async] [End] [Success] Function=ECHO, Workbook=Excel add-in 407248da-0b4e-4409-aa2f-ed4d328610af.xlsx 3/13/2025 13:24:00 Medium CustomFunctions [Execution] [Async] [End] [Success] Function=INCREMENT, Workbook=Excel add-in 407248da-0b4e-4409-aa2f-ed4d328610af.xlsx 3/13/2025 13:24:00 Verbose CustomFunctions [Execution] [Async] [Begin] Function=UPXL.ECHO, Workbook=Excel add-in 407248da-0b4e-4409-aa2f-ed4d328610af.xlsx

[millerds]

Deleting the wef cache helps with this. https://learn.microsoft.com/en-us/office/dev/add-ins/testing/clear-cache#manually-clear-the-cache-in-excel-word-and-powerpoint

[mwilk-drw]

Thanks @millerds . I followed the steps "Automatically clear the cache" in Excel, and upon restarting the issue persist as before.

I also found issue #372 , which seems related. I attempted various suggestions from that discussion and they didn't address the issue either. What's surprising is that @donlvMSFT mentions "on desktop version the performance is much better" - but I am on desktop and what I see is not usable.

In case it's relevant, my Windows.Storage.OneCore.dll is version 10.0.19041.4355.

[millerds]

Do the manual cache deletion.

[mwilk-drw]

Thanks, I followed the steps: Deleted %LOCALAPPDATA%\Microsoft\Office\16.0\Wef\ and confirmed %userprofile%\AppData\Local\Packages\Microsoft.Win32WebViewHost_cw5n1h2txyewy\AC\#!123\INetCache\ doesn't exist. I shut down Excel and Webpack -> npm run build -> npm run start. I observed no improvement.