# Team Keeps Overwriting the Inventory Spreadsheet? The Fix

> Excel saves the whole file, so the last save wins and stock counts vanish. Four fixes you can do this week, and the inventory app that ends the problem.

Source: https://llamapress.ai/people-keep-overwriting-each-other-in-our-inventory-spreadsheet-here-is-the-fix | Updated: 2026-09-02

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Excel saves the whole file, so the last save wins and stock counts vanish. Four fixes you can do this week, and the inventory app that ends the problem.

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![Kody Kendall](https://llamapress-ai-image-uploads.s3.us-west-2.amazonaws.com/jujc1ep8nuqrdiftdfer1ngp833u)

Written by

### Kody Kendall

AI & Software Engineer | Creator of the Leonardo Coding Agent

Updated September 2026

Excel saves the whole file, so two people saving the same inventory spreadsheet cannot both win. The last save replaces the other person's counts, or the file locks and one person waits. Quick fixes buy you a few months. Move the file to OneDrive and turn on co-authoring, or move stock entry into a form that appends rows. The real fix is a database that saves one stock movement at a time and records who made the change. An inventory app built from your spreadsheet does exactly that, and Leonardo can build one from the file you already run.

In short

- Excel overwrites changes because every save writes the entire file, so the last person to save wins.
- Co-authoring only works when the file lives on OneDrive or SharePoint Online, uses .xlsx, .xlsm or .xlsb, and everyone runs a supported version of Excel.
- A form that appends rows stops most overwrites for stock-in and stock-out, but nobody can correct a row from the form.
- Past about five users, no Excel fix gives you row-level locks, an audit trail, or a rule that blocks negative stock.
- An inventory app stores each stock movement as a record and calculates quantity on hand, so nothing gets typed over.

I build the software that turns spreadsheets into apps, and I created Leonardo, the coding agent we use to do it. Inventory spreadsheets cross my desk more than any other kind of file. The complaint is nearly always the same. Two people edited the file on the same afternoon, and one person's counts disappeared. I know where the overwrite happens and what stops it.

![Brown cardboard boxes stacked on white metal warehouse racks, the kind of stock a shared inventory spreadsheet tries to count](https://images.unsplash.com/photo-1587293852726-70cdb56c2866?crop=entropy&cs=tinysrgb&fit=max&fm=jpg&ixid=M3w4NTU2MDF8MHwxfHNlYXJjaHwxfHx3YXJlaG91c2UlMjBpbnZlbnRvcnklMjBzaGVsdmVzfGVufDB8fHx8MTc4ODM2MTg3Nnww&ixlib=rb-4.1.0&q=80&w=1080)

Photo by [CHUTTERSNAP](https://unsplash.com/@chuttersnap?utm_source=leonardo_rails_app&utm_medium=referral) on [Unsplash](https://unsplash.com/photos/brown-cardboard-boxes-on-white-metal-rack-BNBA1h-NgdY?utm_source=leonardo_rails_app&utm_medium=referral)

## Why does Excel overwrite other people's changes?

Excel treats your inventory spreadsheet as one file. When you press save, Excel writes the entire file to disk, every tab and every cell. If a coworker saved 30 seconds earlier, your save replaces their version. Neither of you gets a warning about the cells that changed. Every problem on this page follows from that one fact.

The overwrite shows up in three ways. The first is the shared network drive. Someone opens Inventory.xlsx from \\\\server\\shared, and the next person sees "locked for editing by another user". Microsoft's documentation states that server paths like \\\\server\\folder do not support co-authoring, and the fix is to [put the file on OneDrive or SharePoint](https://support.microsoft.com/en-us/office/excel-file-is-locked-for-editing-6fa93887-2c2c-45f0-abcc-31b04aed68b3). The same page admits that the "another user" is sometimes you. An Excel session left open on a second computer locks everyone out.

The second way is the emailed copy. Someone sends Inventory\_v7\_FINAL.xlsx to the warehouse lead on Monday. By Wednesday there are three versions with different counts in column F, and nobody can prove which count was right.

The third way is co-authoring that does not work. Co-authoring lets several people edit one spreadsheet at once, under strict conditions. The file must sit on OneDrive, OneDrive for Business, or a SharePoint Online library. The format must be .xlsx, .xlsm, or .xlsb. AutoSave must be on. Every person must use Excel for Microsoft 365, Excel for the web, or the mobile apps. Microsoft's [co-authoring documentation](https://support.microsoft.com/en-us/office/collaborate-on-excel-workbooks-at-the-same-time-with-co-authoring-7152aa8b-b791-414c-a3bb-3024e46fb104) lists those conditions. If just one person uses an older version of Excel, everyone else gets the locked error.

Some teams still turn on the old Shared Workbook feature. Microsoft describes Shared Workbooks as "an older feature" with "many limitations" that [has been replaced by co-authoring](https://support.microsoft.com/en-us/office/about-the-shared-workbook-feature-49b833c0-873b-48d8-8bf2-c1c59a628534). In a legacy shared workbook you cannot create tables, add data validation, or protect worksheets. Skip that feature for an inventory file.

## Four fixes you can do this week inside Excel

These four changes take a day or less. Each one removes one cause of overwrites, and I list the limit of each.

**1. Move the file to OneDrive or SharePoint and turn on co-authoring.** Delete the copy on the network drive. Put the spreadsheet in a SharePoint library the whole team can reach. Turn AutoSave on so changes appear within seconds. Check that every person opens the file in Excel for Microsoft 365 or in the browser. The limit: two people typing in the same cell still produce one value. There is no record of who changed the count in F14 from 40 to 4.

**2. Move stock-in and stock-out entry to a form.** Build a Microsoft Form or a Google Form with four fields: SKU, quantity, direction, and reason. Microsoft Forms can open results in an Excel workbook on OneDrive with a live connection. Google Forms writes responses into a linked Google Sheet. Nobody edits shared cells anymore. Each movement becomes a new row with a timestamp. The limit: forms are one-way. A respondent cannot view or fix an existing row from the form. A wrong quantity stays wrong until someone opens the sheet. Quantity on hand still comes from a SUMIF formula in a cell someone can overwrite.

**3. Protect the formula ranges.** Lock the cells that hold the SUMIF, the reorder math, and the SKU list. Leave the entry cells open for typing. Microsoft's [protect-a-worksheet page](https://support.microsoft.com/en-us/office/protect-a-worksheet-3179efdb-1285-4d49-a9c3-f4ca36276de6) is direct about the limit: "Worksheet level protection isn't intended as a security feature." Protection does not stop a person with the password, and the same lock applies to everyone. There is no way to give the warehouse team their rows and the sales team theirs.

**4. One owner per tab, with a change-log column.** The warehouse lead owns the Movements tab. Purchasing owns the Reorder tab. Sales gets a read-only copy. Add two columns to every tab, "Changed by" and "Changed on", and ask people to fill them in. The limit: the log depends on discipline. The person making the change also writes the log entry. People who overwrite counts rarely remember doing it.

The table below compares the four fixes with an inventory app on the five questions operators ask me. Prices are as of this writing.

|  | OneDrive co-authoring | Form intake | Protected ranges | One owner per tab | Inventory app |
| --- | --- | --- | --- | --- | --- |
| Stops overwrites? | Mostly. Same-cell edits still collide | Yes for new movements. Corrections still happen in the sheet | Only for locked cells | Only if people follow the rule | Yes. Each movement is its own record |
| Audit trail? | No per-cell log of who changed a count | Partial. New rows carry a timestamp, later edits do not | No | Typed by hand, so incomplete | Yes. Who, when, why, on every change |
| Works on phones? | Yes, with the Excel app and a Microsoft 365 subscription | Yes. Forms are phone friendly | Same as the file | Same as the file | Yes. Browser page with a scan button |
| Stops negative stock? | No | No | No | No | Yes. The rule rejects the movement |
| Cost | Included with Microsoft 365 | Included with Microsoft 365, or free with Google Forms | Free | Free, plus one person's time | Hosting from $9.99/mo, no per-user fees. Done-for-you builds from $2,000 |

Co-authoring requirements come from [Microsoft's co-authoring page](https://support.microsoft.com/en-us/office/collaborate-on-excel-workbooks-at-the-same-time-with-co-authoring-7152aa8b-b791-414c-a3bb-3024e46fb104). LlamaPress prices are on our [pricing page](https://llamapress.ai/pricing) and [services page](https://llamapress.ai/services).

## Why do those fixes stop working at five or more users?

Past about five people, the problem changes from overwrites to trust. The counts in the sheet stop matching the shelves, and nobody can say when the two drifted apart. Five things cause the drift, and no Excel fix addresses any of them.

There is no row-level lock. Excel and Google Sheets protect ranges, and Google can restrict a range to named people. Neither tool can say "the warehouse team may edit rows for their location only." There is no audit trail. An old version of the file shows the sheet changed. An old version does not show that Sam changed SKU 4410 from 120 to 12 at 3:40 pm. There is no rule that stops negative stock. A cell will happily hold negative 8. There is no phone workflow. Excel mobile edits go through the same whole-file model. There are no reorder alerts unless someone opens the sheet and looks for red cells.

The symptom that tells me a team has hit this wall is the monthly full count. The team closes for half a day, counts every shelf, and retypes the whole quantity column. The count resets the spreadsheet to the truth for about a week. Then the drift starts again. If you recognize that cycle, the older post on [the basic inventory spreadsheet trap](https://llamapress.ai/the-basic-inventory-spreadsheet-trap-scaling-your-operations-in-2025) covers the wider set of problems.

## What does an inventory app do differently?

An inventory app never stores quantity on hand as a typed number. The app stores each stock movement as a record: the SKU, the quantity, the direction, the person, the time, and the reason. Quantity on hand is calculated from the movements every time someone looks. When two people receive stock at the same second, the database writes two rows. Both survive.

The reasons are a fixed list: receipt, sale, transfer, return, adjustment, damage. An adjustment above a set quantity can require an approval from the owner. The app rejects any movement that would take a SKU below zero. The message shows the person what the app thinks is on the shelf. The rule runs in the database, so the rule applies from every screen.

Roles replace the honor system. The warehouse team can record movements and adjust counts at their own location. Sales can look up quantity on hand and cannot change a value. Each person signs in with their own login, so the audit trail names a person. The [guide to adding logins and permissions to a spreadsheet process](https://llamapress.ai/how-to-add-user-logins-and-permissions-to-a-spreadsheet-based-process) shows how those roles get defined.

Reorder points live on each SKU. The app compares quantity on hand to the minimum every night and emails purchasing a list. On the floor, the receiving page is a browser page with a big quantity field and a camera button that reads the barcode. The [phone-first version of this build](https://llamapress.ai/how-to-turn-an-excel-spreadsheet-into-an-app-your-field-team-can-use-on-their-phones) covers what that page needs for gloves and bad lighting. If your inventory feeds customer orders, the same movements model powers [custom order tracking software](https://llamapress.ai/custom-order-tracking-software-that-gives-your-team-one-source-of-truth), so one build can cover both.

## How to move without a big project

Three steps get most teams over without a long rollout. First, export the current sheet as opening balances. The SKU list becomes the products table. The quantity column becomes one opening movement per SKU, dated the day you cut over. Nobody has to clean up the old history, because the opening movement is the starting point.

Second, run both for two weeks. The warehouse records every movement in the app and in the sheet. At the end of each day, compare the two totals. Every difference is a bug in the app or a habit in the sheet, so find both before the cutover. Third, cut over on a Monday morning. Make the spreadsheet read-only that day and never edit the file again.

## When a three-person team should keep co-authoring

Some teams should stop at fix number one. If three people touch the file, at one location, with a few hundred SKUs, co-authoring on OneDrive is enough. If nobody needs to enter stock from a phone, and a wrong count costs you an hour instead of a lost order, keep the spreadsheet. If you are on the fence, the [rebuild or keep Excel decision guide](https://llamapress.ai/should-you-rebuild-your-excel-workbook-as-software-or-keep-using-excel) gives you the thresholds I use.

## How Leonardo builds the inventory app from your spreadsheet

Your spreadsheet already describes the app. The SKU tab is the products table. The Movements or Log tab, if you have one, is the stock movements table. The quantity column with the SUMIF is the calculation the app runs. The reorder tab is the alert rule. When you [upload your inventory spreadsheet](https://llamapress.ai/excel-to-app), Leonardo reads those tabs and proposes the data model. Leonardo then asks about the parts a sheet cannot express, such as who may adjust and what happens below zero.

The output is a standard Ruby on Rails app on a PostgreSQL database. The code lands in your own GitHub repository from the first commit. A human engineer reviews every build before you rely on it. We have converted more than 400 spreadsheets into apps this way. The first upload at [/excel-to-app](https://llamapress.ai/excel-to-app) is free and needs no credit card, so you see the proposed model before you decide anything.

From Spreadsheet to Software

### Stop losing counts to the last save.

Upload the inventory spreadsheet your team fights over. Leonardo turns it into an app where every movement is a record and every change has a name on it.

[Convert My Inventory Sheet](https://llamapress.ai/excel-to-app) [See Order Tracking Apps](https://llamapress.ai/custom-order-tracking-software-that-gives-your-team-one-source-of-truth)

Prefer to talk first? [Contact us](https://llamapress.ai/contact) and we will look at your workbook with you.

## Frequently Asked Questions

### We run our whole inventory on an Excel file and people keep overwriting each other. What should we do?

This week, move the Excel file to OneDrive or SharePoint, turn on AutoSave, and move stock entry into a form that appends rows. Those two steps stop most overwrites for a team of three to five. Past that size, replace the Excel file with an inventory app that stores each stock movement as a record and calculates quantity on hand. You can upload the Excel file at /excel-to-app and see the proposed app before you commit.

### Why does Excel say the file is locked for editing by another user?

Excel shows the locked-for-editing message when the file sits in a location that cannot co-author, such as a network drive path like \\\\server\\folder. Excel also shows the message when one person on the team uses an older version of Excel that does not support co-authoring. Microsoft notes the "another user" is sometimes you, through a second open session. Moving the file to OneDrive or SharePoint Online removes the lock for most teams.

### Can multiple people edit an Excel inventory file at the same time?

Multiple people can edit an Excel inventory file at once through co-authoring. Co-authoring requires the file to be on OneDrive, OneDrive for Business, or SharePoint Online, saved as .xlsx, .xlsm, or .xlsb. AutoSave must be on and every user must be on Excel for Microsoft 365 or the web. Co-authoring still treats the inventory file as one document, so two people editing the same cell produce one value with no record of the change.

### Is Google Sheets better than Excel for a shared inventory?

Google Sheets handles simultaneous editing well and lets you restrict a protected range to named people, which Excel worksheet protection cannot do. Google Sheets still has no per-user row permissions, and Google states that sheet protection should not be used as a security measure. For a shared inventory, Google Sheets removes the file-lock problem and keeps the audit-trail and negative-stock problems.

### How do I track who changed what in a spreadsheet?

In a spreadsheet, the practical options are a change-log column that people fill in by hand, or a form that stamps each new row. Neither method records edits made after the row exists, and neither records the old value next to the new one. An inventory app records who, when, why, the old quantity, and the new quantity on every movement without anyone typing a log entry.

### What is the best way to manage inventory without a spreadsheet?

The best way to manage inventory without a spreadsheet is a database-backed app built on a stock movements model. Each receipt, sale, transfer, and adjustment is a record with a person and a time attached, and quantity on hand is calculated from those records. Add roles so warehouse staff adjust and sales staff view, plus reorder points per SKU. LlamaPress builds that app from the inventory spreadsheet you already use.