Is it really a bad idea to follow "then" with a comma without adding "and" or replacing the comma with the semicolon?

Question

This is from The IBM Style Guide: Conventions for Writers and Editors:

Then is not a coordinating conjunction. You cannot join independent clauses with then unless you add a semicolon or a coordinating conjunction.

Examples (incorrect)

• Click Start then select a program.
• Click Start, then select a program.

Examples (correct)

• Click Start; then select a program.
• Click Start and then select a program

page 46

Note that “then” is not a coordinating conjunction (such as “and,” “or,” and “but”). Using “then” as a coordinating conjunction creates a run-on sentence, as in the following example: “Do this, then do that.”

page 367

In my work as a technical-writer-in-free-time, I often have to write instructions like this one:

1. Here goes the 1st step.
2. Here goes the 2nd step.
3. Open the preferences window, select the Paths tab, and note that the path in the File name field is missing.

Does it mean that the 3rd step in my instruction violates the IBM recommendations? I mean, it is essentially the same as

Open the preferences window, then select the Paths tab, and then note that the path in the File name field is missing.

The first then seems to violate the IBM guidelines, isn't it? Is it really a good idea to replace the first comma there with a semicolon?

Open the preferences window; select the Paths tab and note that the path in the File name field is missing.

Answer 1

#3 is correct as written because it is a series of three independent clauses separated by commas and joined with and.

The most important consideration with a sentence like this is length. Three long clauses joined in this fashion can be difficult for the mind to process.

Your sentence with the semicolon is technically correct, but the location of the semicolon is random. It would work equally well after the word tab. You could also separate all three clauses with semicolons. The ideal choice should depend on clarity.

What you have here is a solution in search of a problem.

Answer 2

Technically, it should have a comma:

Click start, then select a program.

Some people might also write:

Click start and select a program.

Some might take exception to the latter because it is a succession of steps rather than an instruction to do two things simultaneously. However, we do this all the time, for example, "put your foot down and drive", or "pick up your ball and go home".

Also worth considering is that instruction manuals, which your quote sounds like, may adopt an easy-to-follow style over strictly obeying the rules of grammar.

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Your written example #3 does not currently make sense, because noting that something is missing is not really a step. 'To note' something does not mean to do anything about it. If your instruction is simply to make a note of whether it is missing or not, you should say:

Open the preferences window, select the Paths tab, and note whether the path in the File name field is missing.

Or, if it is not meant to be missing, it would be better as:

Open the preferences window, select the Paths tab, and check that the path in the File name field is not missing.

Update: you have advised that the file name is always going to be missing at this stage. In this case, the best way to word that, making it clear that this is something to note as part of the learning process rather than an actual step, would be:

Open the preferences window and select the Paths tab. You will note that the path in the File name field is missing.