Office for Mac Issues

How to Fix Custom Dictionary Is Full Error in Word for Mac

Muhammad Talha Sep 30, 2026 869 views

Question details

The user is encountering an error stating that the custom dictionary is full when using Microsoft Word on a Mac.

Product: Microsoft Word for Mac
Device & OS: macOS
Scenario: Running a spell check or attempting to add a new word to the dictionary in Word for Mac.
Observed behavior: Word displays a 'custom dictionary is full' error prompt, preventing the user from saving new custom words. This usually happens when the dictionary file is corrupted or has reached its size limit.

Before you start

Ensure that your macOS and Microsoft Office suite are updated to the latest versions, as outdated software can sometimes cause false dictionary errors.

Solution 1Recommended

Reset the Custom Dictionary File

Deleting the potentially corrupted dictionary file and creating a fresh one is the most effective way to clear the error.

Microsoft Word stores your saved custom words in a specific container folder on your Mac. If this file becomes corrupted, it will trigger the full error regardless of how many words it actually contains. Resetting it will solve the issue, though you will need to start a new custom word list.

Adjust Word spelling preferences

Open Microsoft Word. Go to the top menu bar, click on 'Word' > 'Preferences', and select 'Spelling & Grammar'. Uncheck the option that says 'Suggest from main dictionary only'.

Locate the Office dictionary folder

Quit Microsoft Word completely. Open 'Finder', click on 'Go' in the top menu bar, and select 'Go to Folder' (or press Shift+Command+G). Type in the path: ~/Library/Group Containers/UBF8T346G9.Office/ and press Enter.

Delete the corrupted file

In the folder that opens, locate the 'Custom Dictionary' file. Right-click on it and select 'Move to Trash'. Empty the trash and restart your Mac.

Create a new dictionary

Launch Microsoft Word again. Navigate back to 'Word' > 'Preferences' > 'Spelling & Grammar' > 'Dictionaries' (or 'Custom Dictionary') and click 'New' to create a fresh dictionary file.

Dictionary Recreated: Your new dictionary is now active. You should be able to add new words during spell checks without encountering the full error.

Solution 2

Test with a New Mac User Account

Testing on a fresh macOS profile helps determine if the dictionary issue is tied to system-wide corruption or just your specific user profile settings.

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Frequently Asked Questions

Why does Word say my custom dictionary is full when I hardly added any words?

This usually indicates that the custom dictionary file (.dic) stored in your Mac's Library folder has become corrupted or experienced a syncing error, rather than actually reaching a word limit. Deleting the corrupted file and creating a new one resolves this.

Will I lose all my saved words if I delete the custom dictionary file?

Yes, deleting the Custom Dictionary file will remove all the custom words you previously added. If you have essential words you want to save, you can try opening the .dic file in a plain text editor (like TextEdit) and copying the word list before deleting the file.

Is there an actual limit to how many words a Word custom dictionary can hold?

While Microsoft Word custom dictionaries do have technical size limits (usually around 64KB for older versions or thousands of entries for newer ones), the 'dictionary is full' error is almost always caused by software bugs or file corruption on macOS, not by exceeding the actual word count limit.

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