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My suggestion is to get a call trace (with strace or similar) of MonitorLM up through when it is clearly hung. This may be too big to send by email to support@wolfram.com. It can be uploaded via http://upload.wolfram.com/. For the "Recipient:"...
The damaged internal code that is printed out, Data[{ Cell[20901203, 381552, 112, 1, 41, "Subsection"], Cell[CellGroupData[{ Cell[20901340, 381557, 902, 23, 52, "Input"], comes from the bottom of the notebook file and might not be...
Near-duplicate of http://community.wolfram.com/groups/-/m/t/424357 .
Works fine for me 10.0.2 on MacOS 10.8.5. You might try a "clean start" of Mathematica in case an initialization file has bad parameters. http://support.wolfram.com/kb/12464
FindRoot is evaluating its first argument before inserting a number for x. Either ignore the warning or convert lstInt into a function that is inert for non-numerical arguments. See http://support.wolfram.com/kb/12502 .
Registering or not registering should have nothing to do with a crash. Since this is repeatable for you, try catching a dump of it. - Start the Mathematica kernel by itself (Start menu - All Programs - Wolfram Mathematica - Wolfram...
Would you provide an overview of how you did it? Someone will have a similar question and your solution could save that person a lot of time.
I asked developers to look at your example. It is a known problem. A correction is in the works for a future release.
Or a notebook file. See the "Add a file to this post" button.
1) Looks like you did not get parentheses matched when re-typing Isaac's example. 2) Could you save what you have in a notebook file (.nb) and attach that file to a post? (With the "Add a file to this post" button.) Simple example attached....