The Saving Preferences menu in the Preferences submenu of the Sequence Editor's Edit menu allows you to control certain options about how the Sequence Editor will save sequences.
The Saving Preferences menu
Export Compressed
When the Sequence Editor saves a sequence, by default it also exports a compressed sequence for that sequence (if the sequence supports compression). This is intended to make using compressed sequences as simple as possible - with this option enabled, the compressed sequence for a sequence will always be up to date, and thus will not have to be recreated during your show (or manually before it). However, for users with very large sequences, creating a compressed sequence may take significant amounts of time, and so this option in the Saving Preferences menu allows you to disable this behavior. If you turn this behavior off, it is recommended that you manually make sure that your sequences each have an up-to-date compressed sequence before your show starts (which you can do for a single sequence via the Export as Compressed command in the Sequence Editor's File menu, or for an entire show or schedule via the Sequence Compressor program).
Verify Load
When the Sequence Editor saves a sequence, it actually saves it to a temporary file first, and then (by default) attempts to reload that temporary file. Only if the load is successful will it actually overwrite the existing "real" sequence file with the newly saved temporary one. This is intended to minimize the potential for a save where something went wrong to cause the user to lose a good (earlier) save. However, this behavior is optional, via this option in the Saving Preferences menu. It is recommended to have this behavior enabled, but if you work with very large sequences that take significant amounts of time to load and save, and are willing to take the risk of a corrupted save overwriting your previous good save file, you might want to turn it off in order to speed up saving.