How do you unmerge cells in many Excel files at once on a Mac?

By Kayabyte · Last updated 11 November 2026

In Excel for Mac, select the range and use Home, Merge & Center, Unmerge Cells, one sheet and one file at a time. That leaves the value only in the top-left cell and blanks below it, so a filter, sort or pivot still misbehaves until you fill the blanks. For a folder of workbooks, Gridhand’s Clean tool has an “Unmerge and fill down” step that does both in one run, with a preview first. It takes .xlsx and .xlsm files only.

Why merged cells cause trouble

A merged cell holds one value but covers several rows or columns. Export that sheet or filter it and only the first row of each block has a value, so “Region: North” appears once and the next five rows show a blank region. Sorting, filtering, importing into another tool and counting by region all go wrong. The usual fix is two steps: unmerge, then copy the value into the empty cells.

The manual way in Excel for Mac

Select the columns that contain merged cells.
Choose Home, then the Merge & Center menu, then Unmerge Cells.
With the range still selected, use Edit, Go To, Special, Blanks. Type =, press the Up arrow, then Ctrl-Return, so every blank cell takes the value above it.
Copy the range and Paste Special, Values, so the formulas become plain values.
Repeat for every sheet that has merged cells, then do the same in the next file.

This is fine for one workbook. With 40 monthly files it is a lot of repeated clicking, and a slip (a range that was too wide, a formula left behind) is easy to miss. Menu names and steps vary a little between Excel versions on a Mac; we have not cited a Microsoft page for these steps, so check them in your own Excel.

What Gridhand can do here

Gridhand is a Mac app we make for batch jobs on Excel files. Its Clean tool has an “Unmerge and fill down” step: it unmerges cells and copies the value into the cells below it. Merges that run across a single row are unmerged without filling. Other Clean steps (trimming spaces, numbers, dates, duplicates, empty rows and columns) stay off unless you tick them.

Things worth knowing before you run it:

The preview shows examples and counts first, and nothing is written until you press Run.
Each file stays the same type, macros included. Cleaned copies go into an output folder you choose, never the folder the files came from, and originals are never modified.
In a workbook with pivot tables, Clean removes no rows or columns; the run report says so. Check the report notes marked “Check these”.
Gridhand reads .xlsx and .xlsm only. A .xls or .numbers file has to be saved as .xlsx first, and a password-protected workbook has to be unlocked in Excel first.
A CSV has no merged cells, so there is nothing to unmerge in one. Gridhand’s Convert tool turns CSV into XLSX if you need that step elsewhere.

Steps with Gridhand

Drop the workbooks, or a whole folder (subfolders can be included), onto the Gridhand window.
Choose Clean in the sidebar and tick “Unmerge and fill down”. Leave the other steps off if you only want this one.
Read the preview and check a few examples.
Choose an output folder and press Run (Cmd-R).
Open one result and compare it with the original, then read the report.

Your first 2 runs are free, each on up to 2 input files; previews are always free. Gridhand Pro is USD 49 once, for 2 Macs, with one year of updates and a 30-day refund. Download Gridhand · Pricing

Questions

Does unmerging keep the value in every row? Yes, with the fill-down part of the step: the value is copied into the cells below it. A merge across a single row is unmerged without filling.

Will it change my original files? No. The results are new files in the output folder you choose.

Does it work on CSV files? CSV files have no merged cells. Use Convert to turn them into XLSX; Clean itself takes .xlsx and .xlsm.

Do I need Excel installed? No. Gridhand does not need Microsoft Excel.

Microsoft and Excel are trademarks of the Microsoft group of companies. Gridhand is made by Kayabyte and is not affiliated with or endorsed by Microsoft.