Every so often we see a question from someone asking why Outlook adds an extra space following apostrophes. This isn’t an Outlook problem, but it is a sign we spend too much time in Outlook…
This is caused by Contextual spelling in Office. Contextual spelling picks up words that are spelled correctly but used out of context, like there and their or pair and pear. Its disabled if you have less than 1 GB of ram as it’s a resource hog. (A really convenient resource hog!)
Check in Tools, Options, Spelling, Spelling & Autocorrect Options. Look for a setting for ‘Use contextual spelling’ and uncheck it.
If you want to use contextual spelling, you can undo the changes it makes in error by pressing Ctrl+Z right after typing the apostrophe. Backspacing then retyping the apostrophe may also take care of it.
See http://office.microsoft.com/en-us/help/HP101194671033.aspx#5 for more information about contextual spelling.