MacBook Air 7.1 (early 2015) freezes for five to ten minutes after login

Recently, my MacBook Air 7.1 (early 2015) has been very slow on startup. That is, the system boots quickly, and then I'm able to login, and the desktop begins to load. Initially, I have control and can open one or two applications, but after about thirty seconds, the desktop freezes. Typically, this lasts around five to ten minutes.

I checked login items under the Users & Groups menu, and there were only two applications listed. I disabled them, but the problem persists.

I was able to view the system.log before the slowdown began, and the last entry with which the log was populated was

(com.apple.imfoundation.IMRemoteURLConnectionAgent): Unknown key for integer: _DirtyJetsamMemoryLimit

Later, once I regained control, I could see that this entry appears in the log a large number of times, about ten to fifty¹ more times during the next ten seconds, and then not again until about five minutes later, when I regain control. My understanding is that this is just recording the fact that the system is running out of RAM, and has to being paging, which would be consistent with the slowdown / loss of control.

The questions are two. First:

1. What is causing the system to hang and how do I fix it?

However, I appreciate that that's a difficult question to answer, and, in any case, I would really prefer to know:

2. How do I figure out what's going wrong?

That is, what other steps do I need to take to understand what's causing the slowdown? It would be nice if I could use htop or something similar to log memory usage during that period, but I'm not sure how to start it running in time. Similarly, I have tried to look through system.log during the same period, including using

cat /private/var/system.log | cut -d: -f4- | uniq -c

to identify the most common messages, but nothing, other than _DirtyJetsamMemoryLimit, jumps out.

1: _{Since repeat messages are logged as ---last message repeated N times--- it's hard to count exactly.}

Solution 1:

This is going back to the basics.

Try a safe boot. Shutdown your machine. Hold down the shift key. Poweron. The boot up will take longer than normal because the filesystem on the startup drive is being checked and repaired as needed. All about safe mode including what features and apps safe boot leaves out. Safe boot uses a software driver instead of using your machines video hardware.

  [http://support.apple.com/kb/ht1455][1]

Secondly,

I'd run etrecheck. Your proprietary stuff gets filtered.

-- Download etrecheck. The download link is at the bottom of the screen. http://etrecheck.com/

-- Run etrecheck. The first five runs are free.

-- How to install, run and report output for the EtreCheck Application https://discussions.apple.com/docs/DOC-250000632

-- Explanation of EtreCheck output by etresoft, the author https://discussions.apple.com/docs/DOC-11591

How to report etrecheck data.

When the report is done, click on the export icon.

click on "Copy report" to copy to the clipboard

Get back in your web browser and access your discussion. Paste you etrecheck output into the code {} block.

which results in...

Robert