Why do I get a Red Exclamation after I have done a Update?

@Frank is quite correct on the staleness indicator but--based on your followup comments in his answer--it sounds like your concern is getting a handle on other people's edits rather than your own edits. Many developers, as you intimated, periodically do an update to freshen the working copy with commits from others, the canonical "pull" model (vs. the "push" model).

Let me digress a moment to shift views to justify my next point more clearly. Consider the typical bug tracking system using the pull model: when others submit or update bugs, you need to go to the website (or client) and search and filter and check for what might have changed on issues you are interested in. Some systems support only that. But the better ones also support the push model: you can subscribe to projects or specific issues so that when something new is posted you automatically receive an email. (I could not work well without this feature!)

The situation is analogous in the subversion domain. Yes, I frequently do an svn update to absorb all changes, but I find it quite helpful to be notified when something I have keen interest in is changed by someone else. And doing this is simple: download Stefan Kung's CommitMonitor that adds push technology to Subversion. This tool sits in the system tray on a Windows system, and lets you specify any number of repositories, either at the root, or at any subdirectory, so you can adjust the resolution as fine as you like. Don't mean to sound like an advertisement--I have no connection with the product or author--but I just found this quite recently and I have found it simple to use, unobtrusive, and clean--it just works.

I have recently seen the red exclamation mark persist after SVN cleanups and updates due to multiple files having the same name but different casing in the same repository folder. Tortoise SVN allows multiple files to exist in the same location with the same name with mixed casing, but Windows does not.

As an example, at one location in the repository, 2 files existed: file.txt and File.txt. When I would go to SVN update the working copy, file explorer would only allow one of these files to exist, so only one would be included in my working copy after an SVN update.

When I ran “check for modifications” on my working copy, Tortoise SVN reported that the file that couldn’t be checked out was missing, since it was not allowed to be checked out to my working copy folder. To resolve this, I deleted one of the duplicative files from the SVN repository and ran an update on my working copy.

A Red exclamation mark tells you that you have modified these files in your working copy, so to get rid of the exclamation marks, you have to either commit the files (update the version in the repository with your modified version) or revert them (throwing away your changes).