I have the following sentence, but I’m not sure if the verb should be conjugated as do or does:
… this means moving away from a convoluted collection of Excel spreadsheets or a cumbersome software that do/does not truly lend…
Excel spreadsheets and convoluted software both refer to outdated ways of doing things, so they share the same semantic purpose in the sentence; they should be grouped. A company could be using either a collection of Excel spreadsheets or a cumbersome software package to solve this problem. They wouldn’t use both at the same time, so or is appropriate. The software would solve the problem, but it does the job poorly. Excel spreadsheets also solve the problem, but poorly. Therefore, the two are related but are not packaged together.
My gut feeling is does because each subject is singular, but when combined with or, they become plural, so do makes more sense.
Which is correct?
This answer follows on from a discussion between us in comment and reply.
We have established that you are offering a better alternative to the two unsatisfactory alternatives you have mentioned (excel spreadsheets and a particular software system.
First of all, both ’do’ and ’does’ will sound awkward because ’or’ is actually used in two logically different ways:
Do you take milk or sugar in your coffee?
This is an inclusive disjunction. You can have one or the other or both.
Would you like coffee or tea?
You can have either one or the other but not both.
But, from our exchange, that you are dismissing both alternatives in favour of a third.
The way to avoid ambiguity between inclusive and exclusive or is to use either before the first.
…either a pile of excel spreadsheets or a cumbersome system….
But then you compound the problem by adding the negative not. The sense of possible ambiguity creeps back in here. The essence of the problem is that you want to move away from A and B. There are various ways to do this. First, you need explicitly to say that they should be
..moving away from a choice between A and B…
Now what you want want to say about A and B is that neither of them lends ….(whatever). You are now clearly talking of discarding both of two alternatives because each one is unsatisfactory in some way. Neither has to be followed by a singular verb. So
… moving away from a choice between A and B neither of which lends …