@shreedhar do you have an antivirus, a firewall or some other malware detection software running?
@shreedhar to rule some things out, please create an empty folder, e.g. C:\empty and set that as your flat-field, dark-frame, hald-clut and startup folder.
@shreedhar also, how long does RT take to start in āsingle editorā mode? I.e. when you give it a single RAW file as command-line argument?
Yes @agriggio the first time I ran your new file, the machine told me that this programme comes from an unknown source, do you really want to run. I clicked yes and also clicked, donāt ask me again. This did not happen to the standard RT 5.3 executable. So this is definitely different.
I never open RT from command line! I just click on the shortcut (that I created on the desktop) and it opens in SETM.
well, would you try once, just for me? you wonāt get hurt, I promise 
Sure I will try!! I know, it sounds stupid to all of you but this command line business is too much !!!
OK @agriggio, I bravely went to command prompt and changed the directory to where your exe file was and typed rawtherapee-test and entered. It took again 25 seconds or so to open SETM. exactly the same as clicking on the shortcut.
@Morgan_Hardwood after changing the flat field and dark frame directories to C:/empty (from the default none), it still takes the same amount of time. 25 seconds.
Please note that it is still faster than before.
- Flat-field (Preferences > Image Processing > Directories)
- Dark-frame (Preferences > Image Processing > Directories)
- HaldCLUT (Preferences > Image Processing > Directories)
- Startup folder (Preferences > File Browser > Image Directory as Startup, either set it to āOtherā and point it to
C:\empty, or set it to āLast visited directoryā and go toC:\emptyusing the File Browser and then close RT - it will start there the next time you run RT)
Yes, @Morgan_Hardwood, I have set Haldcut, Flatfield, Darkframe and the startup directories as C:/empty. It still takes about 25 seconds. Preferences do show the empty folder as the directories for all of the above.
@agriggio I did not compile it myself. I was using the version of 3.5 (the slower of the two) that comes in the debian testing repo, as well as a custom one i downloaded as deb file from <iāll fill in when I get home tonight>
@shreedhar I think I was unclear. what I meant is to start RT from the command line, but passing it a raw file as argument. something like this:
rawtherapee-test.exe "c:\my pictures\awesome.nef"
this activates a āsimplifiedā mode without the file browser. could you please try this and report the time? thanks again!
I did what you said and the time was down to about 17 seconds from the 25 seconds. I put the image file in the C: drive itself, no folders. Also, RT did open just the editor tab, without the file browser.
thanks, this is helpful. Iāll dig deeper
As silly as it sounds, on Win 10 one can try running a program with no internet connection. If āSmartScreenā feature is doing things in the background (checking everything unknown against MS databases), it will warn you, that it needs connection. At least for such issues, I would disable it completely. (The option to do this is getting more hidden with time.)
Any downloaded installerās settings can reveal, that it is āfrom unknown sourceā and so āblockedā. āUnblockingā it manually prevents one additional warning.
AV programs, at least some, also can change their own settings silently when āupgradedā. I certainly didnāt alert anybody yesterday to get this message:
All this might not be relevant here, but trying to control all the Windows security software as much as possible can be sensible when developers are dealing with funny behaviour that only happens on some systems.
Iāve tested the custom-file-chooser-button branch and didnāt find any issue. The startup time on my old dual core i3 2.9 GHz was 12 sec. and now it takes only 5 sec. 
So far, so good.
Even hours later, and several resume-from-sleep cycles, RT is still launching in less then 2 seconds! Even on dirs with dozens of large image files!
More remarkable: when I launch the original rawtherapee.exe it again takes about 50 seconds to start! 
and clicking on the āpreferencesā button, takes at least another 20 seconds to appear.
But when I try the rawtherapee-test.exe; everything is quick & responsive immediately! Not even a restart is necessary. So there were definitely compile (?) bugs/errors in the original RT 5.3 for Windows release.
No, @agriggio just greatly worked around this bugs in gtk3. It may happen that you experience the 20/50 seconds delay now and then when you press one of the file chooser buttons