I have Kstars 3.5.7 installed on a Virtualbox in my Lenovo Thinkpad running Windows 10. I have also run Kstars from my Ubuntu Linux Live USB and the same things occurs.
I have the appropriate Index files installed. When I try to use the Simulator (Telescope Simulator, CCD Simulator, Guide Camera Simulator), I can go to say M31 and then, when I run the Align Module with Capture and Save and Slew to Target using either the Primary CCD or the Guide CCD (simulators of course) and no FW or with FW, Binning 2x2 or 4x4 Primary Scope set to FL 268 and f 4.4 (Sharpstar 61 w/ reducer), with all running fine in INDI Server, KStars crashes. The crash does NOT occur on my Mac also running KStars 3.5.7 with the same parameters as above. Please help. 

I had the same experience with my Ubuntu Mate and Linux Mint machines. I have never had this issue with previous versions of Kstars. If anyone knows a way to install a previous version of Kstars let me know. Unlike Mac or Windows no previous versions of installable files are available for Ubuntu. I sent a bug report hoping this issue will be resolved in future versions of Kstars/Ekos.

I had similar experiences with my Ubuntu 18.04LTS and 20.04LTS systems. That's how I went back to the previous version:
sudo apt remove kstars-bleeding kstars-bleeding-data kstars-bleeding dbg

then I installed it from apt cache:
sudo dpkg -i /var/cache/apt/archives/kstars-bleeding_6%3a3.5.7+202201240912~ubuntu20.04.1_amd64.deb /var/cache/apt/archives/kstars-bleeding-dbg_6%3a3.5.7+202201240912~ubuntu20.04.1_amd64.deb /var/cache/apt/archives/libstellarsolver_1.8+202201171029~ubuntu20.04.1_amd64.deb

Now everything works perfectly.

Hi everyone,

I've just created account to find a solution to exactly this problem which is driving me crazy from 3 days.

I find myself in your identical situation: I have Ubuntu 20.04 installed in oracle VM on my Eagle 3 Pro running W10. Every time I start your same commands in simulator mode, and plate solving starts, after a couples of seconds all kstars crashes. Not knowing what it could be due to, I tried everything in the 3 days, literally everything, up to believe that the amount of RAM assigned to the VM wasan't enough, so I went from 2, 3, 4 up to 8Gb but nothing to do.
I have also submitted more than one bug report with the hope that they will fix it as soon as possible.

P.S. The only thing I can add to the whole situation, is that when I click on the PA icon in the suggestions box below I always get the following warning: 'World Coordinate System (WCS) is enabled. The rotation of the CCD must be set manually in the CCD driver or by resolving an image before proceeding to acquire other images, otherwise the WCS information may not be valid. ' . I tried to insert a random value in the INDI / simulator config / CCD rotation menu, but nothing has changed.

Clear skies
Manuel
 

Hi everyone,

I've just created account to find a solution to exactly this problem which is driving me crazy from 3 days.

I find myself in your identical situation: I have <em>Ubuntu 20.04</em> installed in oracle VM on my Eagle 3 Pro running <em>W10</em>. Every time I start your same commands in simulator mode, and plate solving starts, after a couples of seconds all <em>kstars</em> crashes. Not knowing what it could be due to, I tried everything in the 3 days, literally everything, up to believe that the amount of RAM assigned to the VM wasan't enough, so I went from 2, 3, 4 up to 8Gb but nothing to do.
I have also submitted more than one bug report with the hope that they will fix it as soon as possible.

P.S. The only thing I can add to the whole situation, is that when I click on the PA icon in the suggestions box below I always get the following warning: '<em>World Coordinate System (WCS) is enabled. The rotation of the CCD must be set manually in the CCD driver or by resolving an image before proceeding to acquire other images, otherwise the WCS information may not be valid.</em> ' . I tried to insert a random value in the <em>INDI / simulator config / CCD rotation menu</em>, but nothing has changed.

Clear skies
Manuel

I'm so sorry for have posted multiple times but I've experienced some delays in posting and so I reentered my answers multiple times and then I made also some shot ones.

I don't know even how to delete them. 

Again my apologies for the inconvenience. 

Manuel

Unfortunately I haven't any previous allocated cash files to recover because I've installed kstars, for the first time, directly from the latest -badly- version.

Unfortunately I haven't any previous allocated cash files to recover because I've installed kstars, for the first time, directly from the latest - badly - version.

I also had this happen in 3.5.7 ("stable") today.

I switched to the nightly version (3.5.8 beta) and it seems to work again.

Try this:
sudo apt-add-repository ppa:mutlaqja/indinightly
sudo apt-get update
sudo apt-get install indi-full kstars-bleeding gsc

then reboot and restart Kstars

Ugh. I take it back. Still crashing intermittently in StellarSolver on 3.6.8 beta (ubuntu 20.04.3 on amd64).

I can run an hour or so, but that's about it.

Yes, same here, major fail under Ubuntu 20.04.

It's a sad fact that the instability of KStars/Ekos/INDI is (arguably) the
leading cause of the slow pace of its acceptance in the amateur
astronomy world.  Odd regressions and instabilities have ruined
many a night under the stars for users of KStars/Ekos/INDI.

Just as mine was ruined this evening.

I never know from one release to the next if I am going to be
able to do what are the several basic things I have come to
rely on, that is, connecting, slewing, guiding, plate solving,
polar alignment, image downloading/saving, scheduling.

KStars/Ekos/INDI has needed a way for users easily to step back a
version for, let's see, about a decade, preferably without having
to be connected to the Internet (i.e., in the field, trying to make
things work).  I have despaired of that ever happening.

Tonight isn't the first time I have glanced at the Windows
laptop, and considered other options.  Life is short, observing
time is precious.

Gregory
 

Hi
You can have any previous version you like. checkout the one immediately before the stellarsolver perhaps?
git log
commit f34bcb7d999662145425ce83173adbf5b6f738bb (HEAD -> master, origin/master, origin/HEA
D)
Author: Jasem Mutlaq <This email address is being protected from spambots. You need JavaScript enabled to view it.>
Date:   Fri Mar 11 14:10:39 2022 +0300

   Disable event-driven setScopeStatus from INDI::Telescope since it sets m_Status which
prevents the polling method from working

commit 5033fba01ed2f81ecc8061bea3fea1617014f74b
Author: Jasem Mutlaq <This email address is being protected from spambots. You need JavaScript enabled to view it.>
Date:   Fri Mar 11 13:09:56 2022 +0300

   Fix bug that caused PAA to fail if a driver send HORIZONTAL_COORD as well

commit 836f47c891c53a533fbbebaab5a477582d6431b4
Author: Jasem Mutlaq <This email address is being protected from spambots. You need JavaScript enabled to view it.>
Date:   Fri Mar 11 02:46:21 2022 +0300

   Improve Look n Feel tab

commit 23bb6cbfd8de5d775e902234f96e83ba2e9fcc6c
Author: Robert Lancaster <This email address is being protected from spambots. You need JavaScript enabled to view it.>
Date:   Thu Mar 10 20:56:51 2022 +0000

   updating to StellarSolver 2.1

commit f184fd3785cdc297e6e26f7e7465b61863cbcf6d
Author: Nicolas Fella <This email address is being protected from spambots. You need JavaScript enabled to view it.>
Date:   Wed Mar 9 13:36:24 2022 +0100

   Don't find KAuth
    
   It's not used

Cheers and HTH