Bug reports without an attached log file are usually useless.
Thanks for sharing your solution.
Seems, I've found the cause after examining the trace.log.
Winscp (IEDriveInfo Component) tries to detect/access the non-existing A: drive.
After disabling the floppy drive in the PC BIOS, Winscp starts immediately.
I remember, floppy was disabled before, but for some reasons, the BIOS was reset to defaults 1-2 weeks ago...
Re: Very Slow Startup on Windows 10 (SSD)
Thanks for your report.
I have sent you an email with a debug version of WinSCP to the address you have used to register on this forum.
Very Slow Startup on Windows 10 (SSD)
Winscp 5.9.4 (Build 7333)
Windows 10 1607 (Build 14393.693)running from SSD The start-up of Winscp takes ~10 seconds, even a immediate restart.
On the same Computer (Dual-Boot), but Windows 7 from HDD, Winscp starts almost immediately.
If you need any more informations, log-files etc., just notice me.