Re-installing Oracle 19c on Windows 10: Error in Process: ORACLE_HOME\perl\bin\perl.exe. Error while executing ORACLE_HOME\rdbms\admin\dbmssml.sql Question edited for clarity.
Goal: install Oracle 19c on windows 10 and make a PDB.
Background: I installed Oracle on 2 computers incorrectly (unzipped the oracle 19c file into C:\App\db_home1, instad of into C:\App\oracle\product\19.3\db_home1). I tried fixing this by uninstalling (manually by following these instructions: https://www.youtube.com/watch?v=EHFbk_6ThAQ ). Now i'm trying to re-install.

Problem reinstalling on computer 1:
When i run setup.exe I get an error on the installation step that says [INS-20802] Oracle Database Configuration Assistant Failed.
When I open &quot;installActions2020-09-05_03-48-30PM&quot; I get this error at the bottom: INFO:  [Sep 5, 2020 4:38:02 PM] [FATAL] Error while executing &quot;C:\App\oracle\product\19.3\db_home1\rdbms\admin\dbmssml.sql&quot;. Refer to &quot;C:\App\oracle\cfgtoollogs\dbca\orclglobal\dbmssml0.log&quot; for more details. Error in Process: C:\App\oracle\product\19.3\db_home1\perl\bin\perl.exe
When i go to C:\App\oracle\cfgtoollogs\dbca\orclglobal\dbmssml0.log, it's blank.
Trying Joe's suggestions:
C:\&gt;echo %ORACLE_HOME%
%ORACLE_HOME%

C:\&gt;where sqlplus
'where' is not recognized as an internal or external command,
operable program or batch file.

C:\&gt;C:\App\oracle\product\19.db_home/deinstall/deinstall
The system cannot find the path specified.

C:\&gt;

^ but i have sql plus
^ I never had an env variable named oracle_home. this returns the env variable for the current oracle installation (that isn't complete)
C:\&gt;echo %path%
C:\App\oracle\product\19.3\db_home\bin;C:\Program Files (x86)\Applied Biosystems\QuantStudio Design
'Analysis' is not recognized as an internal or external command,
operable program or batch file.

I think the new installation that i'm trying to install is the only thing the installer is picking up. But I don't know what to do with this message. Where do i run this?


Update: I can connect to the CDB i create, but there's no PDB$SEED.

But I have a seed directory C:\App\oracle\oradata\ORCL\pdbseed




Problem reinstalling on computer 2:
INS-30014: Unable to check whether the location specified is on CFS
Here's what Oracle has to say about this error:

Cause: The location specified might not have the required
permissions.


Action: Provide a location which has the appropriate
required permissions.

All the users (me, admin, all possible users) have full permissions on the D drive.
Another solution I found to INS-30014 is to disable the network adapter. I tried that and it still didn't work. (My ethernet was already disabled, so i disabled the internet and that didn't change anything).
Never delete manually on Windows instead use deinstall.batfrom elevated command prompt from root drive C:\%ORACLE_HOME%\deinstall\deinstall.bat (don't initiate deinstall.bat from inside oracle home)
Remove ORACLE_HOME variable from system/user and ORACLE_HOME/bin from path .
If you removed previous installation and trying to install new database not sure why are you starting with DBCA instead of setup.exe.You mentioned you're trying to install PDB implies you already installed CDB i.e ORCLGLOBAL or am I missing something
Edit:-Deleting registry entries,oracle inventory,services and oracle home directory manually is dirty uninstall if not careful can lead to unintended consequences(current error might be or may not related to previous dirty uninstallation). Oracle provides clean uninstall tools in oracle home directory deinstall.bator gui setup.exe(OUI directory) in oracle home directory (you can check in unzipped folder for directories deinstall and 'oui`).
DBCA should be used only after post install to add new instance/database,new pluggable database or after installing software only.
Since you dirty uninstalled double click setup.exe in oracle home directory (check the image below).

Uninstall tools are shown in red rectangles boxes
Edit:-
On computer one you have conflict in environment from previous installation or leftovers .Verify from command prompt echo %ORACLE_HOME% and where sqlplus if either of the command returns remove those variables alternatively easy way is go to OUI folder as depicted in above picture and next go to bin directory and double click setup.Select all remove everything and go to environment tab select remove everything and start setup again.(I'm assuming you don't have any other Oracle product installations)