[partly solved] Errors after upgrade to 20.04

[GerdG]

I upgraded from 18.04 LTS to 20.04 LTS.
That needed many hours.

Afterwards I ovserved a strange behaviour:

1) The desktop icons fail.
- if I'm clicking on computer, network or trash I get "unknown filetype"
- if I'm clicking on home or a mounted drive instead of a file manager Kid3 (a MP3-tool) is started.

2) Gimp, now installed as a snap, can be started via commandline but doesn't create an icon in the program starter. Other snaps I did not test now.

3) Accessing some folders on my Synology NAS now require an authentication to "run gvfsd-admin daemon". (That might be something else. I had problems with the NAS before.)

I'm using Cinnamon but the same happens with Gnome.

What can I do?

Debug information created by: ubuntu-bug linux.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: linux-image-5.4.0-48-generic 5.4.0-48.52
ProcVersionSignature: Ubuntu 5.4.0-48.52-generic 5.4.60
Uname: Linux 5.4.0-48-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.9
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: gerd 3533 F.... pulseaudio
CasperMD5CheckResult: skip
CurrentDesktop: X-Cinnamon
Date: Fri Oct 2 21:15:33 2020
HibernationDevice: RESUME=UUID=e278c602-babd-4c98-9f33-2269bbe5b086
InstallationDate: Installed on 2015-07-13 (1907 days ago)
InstallationMedia: Ubuntu 15.04 "Vivid Vervet" - Release amd64 (20150422)
MachineType: ASUSTeK Computer Inc. K53SV
ProcFB: 0 i915drmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.4.0-48-generic root=UUID=80d61289-da9f-4b8c-ae8e-34b245393d36 ro splash quiet nouveau.runpm=0
RelatedPackageVersions:
 linux-restricted-modules-5.4.0-48-generic N/A
 linux-backports-modules-5.4.0-48-generic N/A
 linux-firmware 1.187.3
SourcePackage: linux
UpgradeStatus: Upgraded to focal on 2020-09-30 (1 days ago)
dmi.bios.date: 09/26/2011
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: K53SV.315
dmi.board.asset.tag: To be filled by O.E.M.
dmi.board.name: K53SV
dmi.board.vendor: ASUSTeK Computer Inc.
dmi.board.version: 1.0
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 9
dmi.chassis.vendor: ASUSTeK Computer Inc.
dmi.chassis.version: 1.0
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrK53SV.315:bd09/26/2011:svnASUSTeKComputerInc.:pnK53SV:pvr1.0:rvnASUSTeKComputerInc.:rnK53SV:rvr1.0:cvnASUSTeKComputerInc.:ct9:cvr1.0:
dmi.product.family: K
dmi.product.name: K53SV
dmi.product.sku: To be filled by O.E.M.
dmi.product.version: 1.0
dmi.sys.vendor: ASUSTeK Computer Inc.

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This change was made by a bot.

[GerdG (gerdg)]

Update
My problem is partly solved.
After searching dozens of webpages for hints I found one for my second problem that Gimp (snap) is not visible in my program starter. Other snaps were visible!

There "sudo apt install gnome-software-plugin-snap" was recommended.
I tried but Gimp was still missing.
But - strange as it seems - the problem with the desktop icons was gone. Now nautilus opens when clicking on one of the drive icons or on trash.

Now i created my own, small gimp.desktop and it worked. So I assume some error in the original desktop file.

The third problem with the synology "home" folders is still there but might have other causes.