Too inefficient Rated 1 out of 5 stars

I loaded a message in Thunderbird 10, which contained a winmail.dat attachment (~1.2 MB). As a result of that I received for about 10 minutes numerous messages:

"A script on this page may be busy, or it may have stopped responding. You can stop the script now, or you can continue to see if the script will complete.

Script: chrome://lookout/content/tnef.js:1105"

I clicked Continue on each of them. After that I tried to open one of the resultant attachments and again received numerous messages with the same text. During that I noticed that the memory usage of Thunderbird fluctuated widely (it doubled several times for brief moments).

After several minutes Thunderbird finally showed an Open dialog window.