Either the Editor or the Project preferences (or both) are left open (in foreground, bg, or only a tab in the header), the PIE related operations (stop/eject/possess) will cause the editor to raise the memory usage about ~200mb per Preferences Window sessions. The memory usage would raise on each PIE ops until the point the system runs out of memory and Editor/System can crash. When you close the preferences windows the memory gets released. I also experience slowdowns in the preferences window open and close ops, and the PIE operations are also lagging considerably which takes a couple of seconds to execute, while the preferences windows are open.
The 4.14.0-preview 1 was the first build that produce this error, 4.13.2 and before were not affected by this problem.
Tested with 4.14.0 prev1, prev2, both the launcher and source 4.14.0 release versions, and the most recent 4.14 branch (source). All are affected by the issue.
Why a window left in the background can cause issues at all? I usually leave them for quick access, but i don’t expect them to be active until i bring them to the front.
Yup, I opened up my project, and ran a preview with no extra windows open. Maybe a change of about 50MB or so in mem usage. Opened up the editor preferences, and previewed again. Upon running preview, memory jumped by about 300MB, and then again when closing.
I noticed memory issues too, in certain cases when there was issue with physic collision settings of static meshes. Once i removed the static meshes, memory seems okay again.
The fix for this touches a lot of critical files and was deemed too risky for a hotfix. Depending on the severity of the bug, these types of fixes sometimes make it into hotfixes, but this was not the case here.
One of the main reasons is that the simple workaround is to close the Project Settings window while working.