Lately, for me, Chrome freezes immediately after opening the ‘Open Dialog Box’ when attempting to attach a file to an email or during the process of attaching the file to an email. This can happen in any web application using Chrome when using the ‘Open Dialog Box’ (And possibly the ‘Save Dialog Box’.
I have found (for me) that turning off Hardware Acceleration in Chrome fixes the problem.
Google Chrome
1) Click Settings
2) Scroll to the bottom and click Advanced Settings.
3) Under the ‘System’ section, turn off ‘Use hardware acceleration when available’.
4) Relaunch Chrome.