Chrome, Firefox, and Safari's browser doubles in size automatically without any prompt from me

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Level 1

9 points

Chrome, Firefox, and Safari's browser doubles in size automatically without any prompt from me

my browser automatically increases in size. While I am reading an email or just surfing on both Chrome and Firefox. It will suddenly enlarge to 200% or more. I have to type in command - and then click on a little dialogue box in the browser address line to go back to 100%. This happens on all of our iMacs. I am using Ventura 13.7.8 on a 27", my wife's 24" iMac is using Tahoe 26.1. My macbook pro is also using Tahoe.

I hope you can understand my problem

Thx, Steve

MacBook Pro (M5, 2025)

Posted on Dec 19, 2025 4:31 PM

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Answer 1

John Galt

Level 10

155,414 points

Dec 19, 2025 5:41 PM in response to StStephen69

⌘ + is the "zoom in" key chord and ⌘ - is its converse.

I understand that it's occurring spontaneously though, and it obviously should not. Are you aware of any third party customization apps that may be common to all those Macs?

If you are not sure EtreCheck might provide a clue. How to use the Add Text Feature When Posting Large Amounts of Text, i.e. an Etrecheck Report - Apple Community describes how to use it and how to post its report in a reply to this Discussion. Should you choose to avail yourself of it please follow those instructions with care.

Also, investigate each Mac's Accessibility settings: Change Accessibility settings on Mac - Apple Support. It would affect everything system-wide though, not just browser apps.

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Answer 2

Dec 19, 2025 6:40 PM in response to StStephen69

One possibility is two-finger zooming on the trackpad, accidentally as you scroll (which is also a two-finger gesture). Zoom can be done with a two-finger spread or a two-finger double tap (smart zoom). What you’re seeing sounds like smart zoom.

One or both can be disabled in System Settings > Trackpad > Scroll & Zoom.

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Answer 3

StStephen69 Author

Level 1

9 points

Dec 19, 2025 8:55 PM in response to John Galt

I am not aware of any third party apps. Also this happens on all 3 of my computers. All 3 are of different ages.

I did an etrecheck scan. I cant under stand it. It says that I have no major problems just some minor ones.

None of it says anything about how my browsers double in size with no prompting.

Thx

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Answer 4

Dec 20, 2025 9:47 AM in response to StStephen69

< sophos >

You would exppect runtime to be less then 3 minutes...

< Runtime: 4:07 >

Third party AntiVirus is not recommended— it typically does nothing but add issues to the macOS and competes directly with Apple’s own built in security:

macOS antivirus - Protecting against malware in macOS - Apple Support

Security and your Apple Account Security and your Apple Account - Apple Support

Apple Platform Security - Apple Apple Platform Security - Apple Support

Look for some official uninstaller.

For your third party app—if in doubt search the developers website or contact their: Support/Help/FAQ/Uninstaller

Contact a third-party vendor - Apple Support

The current stable release of Tahoe including bug fixes, security updates is macOS 26.2

Keep your Mac up to date - Apple Support

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