In short, URL rich previews in Messages are stored permanently in iCloud under “Messages” but under “System Data” on iOS and MacOS devices.

It’s irritating behavior as there is no way to view which previews are taking up the most storage (often hundreds of MBs from a single URL) and thus no way to efficiently delete.

My solution which was able to drastically decrease storage usage on my Mac and iPhone from 80+ GBs to ~2 GBs:

Download iMazing (or any 3rd party backup service)
Backup Messages to your computer
Export Messages as Excel files (or CSV)
Backup Message attachments as you see fit
Set iPhone and Mac to delete messages after 1 year as opposed to storing them forever.
Save Excel/CSV files to Google Drive or another service of your choice so they are indexed and searchable (incredibly only 50 MB for 3000+ chats)
Repeat yearly to ensure no messages are lost

Comments

this_for_loona t1_jcvhcu3 wrote on March 19, 2023 at 9:38 PM

#2,273,567

How did you figure this out?

justachos OP t1_jcvhxz7 wrote on March 19, 2023 at 9:42 PM

#2,273,614

Replying to this_for_loona (#2,273,567)

On macOS there is a parallel "system data" problem, I searched for the oversized folder, found a bunch of cache files with an unusual extension, found an online converter and realized it was a URL preview from messages.

this_for_loona t1_jcvjje4 wrote on March 19, 2023 at 9:52 PM

#2,273,726

Replying to justachos (#2,273,614)

Damn. Thats pretty clever. Now i gotta try this out.

What ios backup software do you recommend?

And i assume there's no way to put the messages back if this turns out to not fix my issue?

00cho t1_jcvldfp wrote on March 19, 2023 at 10:05 PM

#2,273,851

Replying to this_for_loona (#2,273,726)

In the OP, it specifies iMazing, which is for backing up iOS.

SomegalInCa t1_jcvyjc2 wrote on March 19, 2023 at 11:50 PM

#2,274,671

Doesn’t deleting message’s conversation/ bubble get rid of them ? (Well in 30days cause it sits in recently deleted)

justachos OP t1_jcvzcro wrote on March 19, 2023 at 11:56 PM

#2,274,729

Replying to SomegalInCa (#2,274,671)

In theory it should, but it often does not. The data will remain on your phone and be continually backed up into iCloud. Further, there is no easy way to go back and delete all URLs. Lastly, you would be losing that data permanently, while using the described backup method, you lose nothing.