DB client tool -- To get the error message when open toad oracle client
Depending on YouTube video from @Philᵀᴹ, I have done this problem and I will try to list all I know and every step as following content, Hopefully I can help someone who has the same issues.


Download and Install Toad for Oracle v12.10


Open it you should can not use like as below error message


Download Instant Client 12.2


Unzip it and move it to anywhere you like (for example C:\app\instantclient_12_2)


Go to Control Panel\All Control Panel Items\System-->Environment Variable to "Add" TNS_ADMIN as like below picture


The same path to "Edit" Path like as following picture



OK done with toad client


To move your old tnsnames.ora to C:\app\instantclient_12_2 (for example)






Done all