[SOLVED] Can't install GRUB (Debian Buster) during installation on portable SSD Samsung T5 drive and latest win 10 pro not detected

I am trying to install Debian Buster on a portable Samsung T5 SSD drive and I have windows 10 Pro installed already on a separate internal laptop (Lenovo) drive.

But I can't install GRUB. GRUB is saying failed to install on the hard drive where the Debian buster is being installed. And Grub is not detecting the latest Windows Pro either. Here is the error log saved from the HTTP server.

Can anybody kindly tell me what I should do?

I have kept the installation screen open. I did not turn it off. So I can fix it at the installation point.

Code:14:01:46 os-prober: debug: running /usr/lib/os-probes/50mounted-tests on /dev/sdb1
Jan 9 14:01:46 50mounted-tests: debug: /dev/sdb1 type not recognised; skipping
Jan 9 14:01:46 os-prober: debug: os detected by /usr/lib/os-probes/50mounted-tests
Jan 9 14:01:46 os-prober: debug: /dev/sdb3: is active swap
Jan 9 14:01:46 os-prober: debug: running /usr/lib/os-probes/mounted/05efi on mounted /dev/sdc1
Jan 9 14:01:46 05efi: debug: Not on UEFI platform
Jan 9 14:01:46 os-prober: debug: running /usr/lib/os-probes/mounted/10freedos on mounted /dev/sdc1
Jan 9 14:01:46 10freedos: debug: /dev/sdc1 is a FAT32 partition
Jan 9 14:01:46 os-prober: debug: running /usr/lib/os-probes/mounted/10qnx on mounted /dev/sdc1
Jan 9 14:01:46 10qnx: debug: /dev/sdc1 is not a QNX4 partition: exiting
Jan 9 14:01:46 os-prober: debug: running /usr/lib/os-probes/mounted/20macosx on mounted /dev/sdc1
Jan 9 14:01:46 macosx-prober: debug: /dev/sdc1 is not an HFS+ partition: exiting
Jan 9 14:01:46 os-prober: debug: running /usr/lib/os-probes/mounted/20microsoft on mounted /dev/sdc1
Jan 9 14:01:46 20microsoft: debug: /dev/sdc1 is a FAT32 partition
Jan 9 14:01:46 os-prober: debug: running /usr/lib/os-probes/mounted/30utility on mounted /dev/sdc1
Jan 9 14:01:46 30utility: debug: /dev/sdc1 is a FAT32 partition
Jan 9 14:01:46 os-prober: debug: running /usr/lib/os-probes/mounted/40lsb on mounted /dev/sdc1
Jan 9 14:01:46 os-prober: debug: running /usr/lib/os-probes/mounted/70hurd on mounted /dev/sdc1
Jan 9 14:01:46 os-prober: debug: running /usr/lib/os-probes/mounted/80minix on mounted /dev/sdc1
Jan 9 14:01:46 os-prober: debug: running /usr/lib/os-probes/mounted/83haiku on mounted /dev/sdc1
Jan 9 14:01:46 83haiku: debug: /dev/sdc1 is not a BeFS partition: exiting
Jan 9 14:01:46 os-prober: debug: running /usr/lib/os-probes/mounted/90linux-distro on mounted /dev/sdc1
Jan 9 14:01:46 os-prober: debug: running /usr/lib/os-probes/mounted/90solaris on mounted /dev/sdc1
Jan 9 14:01:53 grub-installer: info: Installing grub on '/dev/sda'
Jan 9 14:01:53 grub-installer: info: grub-install does not support --no-floppy
Jan 9 14:01:53 grub-installer: info: Running chroot /target grub-install --force "/dev/sda"
Jan 9 14:01:53 grub-installer: Installing for i386-pc platform.
Jan 9 14:01:55 grub-installer: grub-install: warning: this GPT partition label contains no BIOS Boot Partition; embedding won't be possible.
Jan 9 14:01:55 grub-installer: grub-install: error: embedding is not possible, but this is required for cross-disk install.
Jan 9 14:01:55 grub-installer: error: Running 'grub-install --force "/dev/sda"' failed.
Jan 9 14:01:58 main-menu[405]: (process:26948): dpkg-divert: warning: diverting file '/sbin/start-stop-daemon' from an Essential package with rename is dangerous, use --no-rename
Jan 9 14:01:58 main-menu[405]: (process:26948): dpkg-divert: warning: diverting file '/sbin/start-stop-daemon' from an Essential package with rename is dangerous, use --no-rename
Jan 9 14:01:58 main-menu[405]: (process:26948): File descriptor 3 (pipe:[12043]) leaked on lvdisplay invocation. Parent PID 27138: /bin/sh
Jan 9 14:01:58 main-menu[405]: (process:26948): File descriptor 4 (/dev/tty0) leaked on lvdisplay invocation. Parent PID 27138: /bin/sh
Jan 9 14:01:58 main-menu[405]: (process:26948): File descriptor 5 (/dev/tty0) leaked on lvdisplay invocation. Parent PID 27138: /bin/sh
Jan 9 14:01:58 main-menu[405]: (process:26948): File descriptor 6 (/dev/tty0) leaked on lvdisplay invocation. Parent PID 27138: /bin/sh
Jan 9 14:01:58 main-menu[405]: (process:26948): Volume group "sdb" not found
Jan 9 14:01:58 main-menu[405]: (process:26948): Cannot process volume group sdb
Jan 9 14:01:58 main-menu[405]: (process:26948): dpkg-divert: warning: diverting file '/sbin/start-stop-daemon' from an Essential package with rename is dangerous, use --no-rename
Jan 9 14:01:58 main-menu[405]: WARNING **: Configuring 'grub-installer' failed with error code 1
Jan 9 14:01:58 main-menu[405]: WARNING **: Menu item 'grub-installer' failed.
Jan 9 14:02:13 main-menu[405]: INFO: Modifying debconf priority limit from 'high' to 'medium'
Jan 9 14:02:13 debconf: Setting debconf/priority to medium
Jan 9 14:02:14 main-menu[405]: DEBUG: resolver (libgcc1): package doesn't exist (ignored)
Jan 9 14:02:14 main-menu[405]: INFO: Falling back to the package description for brltty-udeb
Jan 9 14:02:41 main-menu[405]: INFO: Falling back to the package description for brltty-udeb
Jan 9 14:02:41 main-menu[405]: INFO: Menu item 'save-logs' selected
Jan 9 14:03:30 kernel: [ 963.817265] TCP: request_sock_TCP: Possible SYN flooding on port 80. Sending cookies. Check SNMP counters.
Jan 9 14:03:33 kernel: [ 966.479886] TCP: request_sock_TCP: Possible SYN flooding on port 80. Sending cookies. Check SNMP counters.