Breaking large document into multiple smaller ones

Do a "Save As" (as mentioned above) to the new document, that normally reduced the file size dramatically.

Lots of room to make mistakes, so don't touch your original document and make sure you have backup copies.

Very true.

There are scripts out there to make the process of splitting a large document into multiple small ones an accident-free, simple, one-click operation, not least of which is my (not free) https://www.id-extras.com/products/extract-pages/

Might be worth looking into if you're doing a lot of this.

@jblair1948 

As @James Gifford—NitroPress pointed out - if you make a copy of your file - outside of InDesign - and keep working on it - new Undo History is being added.

In order to purge the Undo History and do a basic housekeeping - you need to do Save As from withing InDesign.

IDMLing also removes all previews - and InDesign will re-generate them when you open this IDML file.

But one more thing - what James didn't mention - are your images LINKED - placed using Ctrl+D and kept as links - or EMBEDED - you've done copy&paste from some other application or manually selected an option for the link?

There are only few situations that you could embed something in the InDesign file - otherwise it should never be done.

CS4 is old enough that some of this may not be quite the same, but the way I would break up a document is to make X copies (four, in your case) and then carefully delete the unwanted pages from each. Lots of room to make mistakes, so don't touch your original document and make sure you have backup copies.

As for the file size(s), what I think you've run into is the fairly common (integral, really) ID file bloat. ID, like Word and some other apps, saves tons of undo, preview and other data with each save. This can add up until your four-page resume is 4-5GB in size.

The solution is to save each file using Save As to a new filename, which purges nearly all of that "junk in the trunk." It's good practice on any project file that's developed over time or continually edited, to do a 'Save As' at intervals — daily isn't too often, for an active project — both to clear this bloat and give you a chain of recoverable backups. (The next frantic post from users like yourself is often how to recover a huge, bloated, broken file that won't open any more... 😛 )

If that doesn't work in reducing the file sizes (and it should, but...) is to save or export each file to IDML format (which I think exists in CS4), then open that file and save again as INDD under a new name. That does the purge above and some significant structural rewriting that can clear up all kinds of small faults and glitches.

Ask away if that doesn't solve your issues.