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Apple mail suddenly stopped loading messages bodies and hugs over 100% CPU, weird activity window

Apple Mail stopped few days ago to download all new messages content. Headers are read in, but not bodies of the messages. I noticed it unfortunately with all Apple Support Communities messages, but it seems to affect other mails.

Mail is stuck to report a weird Activity (few messages only and no progress!). See picture below.


Clicking on Maibox->rebuild or synchronize does not seemingly do anything.

Mail CPU usage is continuously slightly over 100%


I run Mail from the same user account on a MacBook Pro 2015 (running Catalina 10.15.7 as well) and did not encounter any problem. So this problem happened only on my iMac late 2013


Catalina 10.15.7

Mail 13.4 (A single iCloud user registered, other users disabled temporarily)

iMac late 2013


Any idea what should I do? Br


iMac 27″, macOS 10.15

Posted on Apr 3, 2021 8:28 AM

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Question marked as Top-ranking reply

Posted on Apr 7, 2021 1:34 PM

I erased my iCloud account totally from my Mac. Of course when it asked me, I accepted to keep local copies of whatever data seemed to be important, Contacts, Calendar, etc...

https://support.apple.com/en-gb/guide/mail/mail35803/mac


The result is: Apple Mail back, up and running ok so far. Tx everyone for your help!

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Question marked as Top-ranking reply

Apr 7, 2021 1:34 PM in response to claude_210

I erased my iCloud account totally from my Mac. Of course when it asked me, I accepted to keep local copies of whatever data seemed to be important, Contacts, Calendar, etc...

https://support.apple.com/en-gb/guide/mail/mail35803/mac


The result is: Apple Mail back, up and running ok so far. Tx everyone for your help!

Apr 4, 2021 8:35 AM in response to claude_210

Please navigate to www.Etrecheck.com and download the free version of EtreCheck. Once you have you downloaded the app and installed it, please run the report and save it. This report will help us get a good idea what has been installed on your system and help us be able to diagnose what may be wrong.


When you have your report, you can attach it when you reply to this message and we can then review it and help you determine what is needed to get your system running well again. 


For instructions on how to download your EtreCheck report and attach it to your reply to this message please click https://discussions.apple.com/docs/DOC-250000211


Apr 4, 2021 8:04 AM in response to rkaufmann87

Tx for your advice and time, rkaufmann87!


I restarted my machine in Safe mode to no avail. The sluggishness and the absence of some email content was still there, as well as the continuous CPU hugging. The activity window looks the same, no progress on it. Needless to say, returning to the normal logging mode didn't bring any change.


Next, I reinstalled Catalina, -as the apple pages advise to do- to very little avail: I can now force Mail to read the content of some of the empty mail by clicking on Mailbox->rebuild. But the whole Mail application is still sluggish and unpredictable. Creating a new Mailbox demanded Mail to be restarted to succeed.


The problem is definitely on my iMac (late 2013) since Mail still runs fine on my other machine (MacBook pro 2015, same configuration same OS version), with a short peak CPU time of 30% when I press on "Get Mail" button and quickly returning to a nice 0%...


This bug is quite annoying. I am seriously thinking of getting rid of Mail on my iMac and replace it with a more trustable application.


Tx again for your help!

--

Claude


Apple mail suddenly stopped loading messages bodies and hugs over 100% CPU, weird activity window

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