I followed the various steps & see the same problem.
Along the way I manually tidied what looked like old entry in etc/apt/sources.list.d/insync.list; same problem seen.
Here’s step-by-step commands plus output:
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys ACCAF35C
Executing: /tmp/apt-key-gpghome.qoVIVfNjRL/gpg.1.sh --keyserver keyserver.ubuntu.com --recv-keys ACCAF35C
gpg: keyserver receive failed: Server indicated a failure
sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys ACCAF35C
Executing: /tmp/apt-key-gpghome.6r0FhFFZ75/gpg.1.sh --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys ACCAF35C
gpg: key A684470CACCAF35C: 1 signature not checked due to a missing key
gpg: key A684470CACCAF35C: "Insynchq Inc <services@insynchq.com>" 1 new signature
gpg: Total number processed: 1
gpg: new signatures: 1
gpg: invalid key resource URL '/tmp/apt-key-gpghome.6r0FhFFZ75/graphics:darktable.asc.gpg'
gpg: keyblock resource '(null)': General error
gpg: key 7721F63BD38B4796: 2 signatures not checked due to missing keys
gpg: key A684470CACCAF35C: 1 signature not checked due to a missing key
gpg: key 040524A84C70D8B5: 1 signature not checked due to a missing key
gpg: key 76F1A20FF987672F: 1 signature not checked due to a missing key
gpg: key 7FCC7D46ACCC4CF8: 2 signatures not checked due to missing keys
gpg: key A8AA1FAA3F055C03: 2 signatures not checked due to missing keys
gpg: key 040524A84C70D8B5: 1 signature not checked due to a missing key
gpg: key 6D975C4791E7EE5E: 2 signatures not checked due to missing keys
gpg: key 3B4FE6ACC0B21F32: 3 signatures not checked due to missing keys
gpg: key D94AA3F0EFE21092: 3 signatures not checked due to missing keys
gpg: key 871920D1991BC93C: 1 signature not checked due to a missing key
gpg: Total number processed: 22
gpg: skipped new keys: 22
cat /etc/apt/sources.list.d/insync.list
deb http://apt.insynchq.com/ubuntu bionic non-free contrib # disabled on upgrade to bionic
deb http://apt.insync.io/ubuntu bionic non-free contrib
[edit /etc/apt/sources.list.d/insync.list]
cat /etc/apt/sources.list.d/insync.list
# deb http://apt.insynchq.com/ubuntu bionic non-free contrib # disabled on upgrade to bionic
deb http://apt.insync.io/ubuntu bionic non-free contrib
sudo apt update
sudo apt autoremove
Setting up insync (3.1.9.40821-bionic) ...
dpkg: error processing package insync (--configure):
installed insync package post-installation script subprocess returned error exit status 1
Errors were encountered while processing:
insync
E: Sub-process /usr/bin/dpkg returned an error code (1)
sudo apt install insync
Reading package lists... Done
Building dependency tree
Reading state information... Done
insync is already the newest version (3.1.9.40821-bionic).
0 to upgrade, 0 to newly install, 0 to remove and 11 not to upgrade.
1 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Do you want to continue? [Y/n]
Setting up insync (3.1.9.40821-bionic) ...
dpkg: error processing package insync (--configure):
installed insync package post-installation script subprocess returned error exit status 1
Errors were encountered while processing:
insync
E: Sub-process /usr/bin/dpkg returned an error code (1)