Geany version 1.37 "Wolbam" (built on or after 2020-11-09) Using GTK+ v3.24.5 and GLib v2.58.3 runtime libraries
Linux wirth 4.19.0-16-amd64 #1 SMP Debian 4.19.181-1 (2021-03-19) x86_64 GNU/Linux
Computer is an old ASUS Gigabyte box with 4 gigabytes of RAM and a 128 gigabyte SSD.
When Geany is started from a terminal, it takes a couple of minutes to open all project files (166 in this example) and operates correctly for normal activities. Attempting to close the project (menu: Project -> Close) goes through the motion of closing files individually, probably all of them but the failure might be occurring partway through. Geany terminates and leaves only a message stating "segmentation fault" in the starting terminal.
I start Geany from a desktop link under usual operation but there is no information after the failure that way.
A variety of projects with smaller open file counts behave correctly. I don't know where the file count threshold might be.
It is possible to close all files separately, then close the project, with the intent to open another. The result is a project file with no record of files in the project which must be re-opened manually. But using the menu: File -> Close All fails in the same way.
A separate project with 47 open files will open and close correctly without Geany terminating. The project file still has the file list available for next project open.
Possibly a related fault: sometime the close project for a smaller project will go through the motions of closing all files but will leave them still open. I have no more information on when it might happen.