"Please Excuse My Dear Aunt Sally." Remember that from algebra class? This memory aid is helpful to understand the order of operations required to get the correct answer when solving algebraic equations.
Similarly, when it comes to working with FDO, sometimes, it's all about order of operations.
The following workflow, innocent as it is, will result in a freeze/indefinite hang:
1. Connect to an FDO data source in AutoCAD Map 3D.
2. Select many features (I selected 809 points)
3. In the AutoCAD Properties Pane, try to "globally" edit the value of one attribute for all of your selected features.
Sadly, even if Auto Checkout is enabled, you're just not gonna get anywhere. You'll likely have to End Process for acad.exe in Task Manager.
Now, augment your workflow by adding a step:
2. Select many features (I selected 809 points).
3. Hit Check Out (same as running MAPCHECKOUT).
4. In the AutoCAD Properties Pane, try to "globally" edit the value of one attribute for all of your selected features.
Result: almost an immediate change!
Finally, be sure to Check In your features by clicking the button or by running MAPCHECKINALL.
Lesson: if you follow order of operations, you're almost guaranteed smooth sailing!