Category: Troubleshooting

“Certificate couldn’t be read” errors in Mail.app

Corporate mail servers often used SSL certificates, and sometimes these certificates expire. At that point you may start getting “Certificate couldn’t be read” errors in Apple’s Mail.app.

According to Apple, permanently accepting a self-signed SSL certificate may fix the problem.

  1. Click the Show Certificate button in the error message.
  2. Hold down the option key and drag the certificate icon out of the error window to your desktop.
  3. Double-click the certificate icon on the desktop, and choose X.509 Anchors from the pop-up menu. Click Add. You must have permission to administer the computer for this procedure to work.
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Java error message: Several Java Virtual Machines running in the same process

When attempting to launch browser-based SCORM courseware, people have been getting the error: “Several Java Virtual Machines running in the same process caused an error”

Apparently many people have this issue since upgrading java. I came across it because it can affect the delivery of elearning courses if the learning management system relies on a java-applet based scorm adaptor to communicate.

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When colspan property doesn’t appear to work in Firefox or Safari

When building web applications I often use display styles to show or hide divs or table rows as needed. On one project, I found that the “colspan” property did not seem to work in Firefox or Safari. This was because I had incorrectly used display:block to style the TR element, instead of display:table-row. A demo is below, and the code follows.

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