MailKit Extension shows "Loading..." longer than usual esp. for emails with attachments

Number:rdar://FB12796974 Date Originated:2023-07-30
Status:Investigating Resolved:
Product:macOS Mail Product Version:
Classification:Bug Reproducible:
I'm developing a MailKit Mail Extension using the MEMessageSecurityHandler capability and after enabling it and selecting a message, it takes longer than usual to display it, sometimes taking over 10 seconds to display (especially on e-mails that include attachments). I noticed this happens even with the sample WWDC21 MailKit app/Mail Extension, which is odd because there isn't any long-running functions in the code. Disabling all Mail Extensions allow selected messages to be displayed nearly instantly as expected. To try to reproduce: 1. build and run 2. Goto Mail > Settings > Extension > check: SampleMailExtensions 3. select an email with an attachment 4. "Loading..." spinner appears in the Message viewer and takes over 10 seconds on most (but not all) Macs I've tried before the body is displayed

Ventura 13.5


From Apple

Mail seems to be calling into the extension multiple times. We are tracking this internally

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