ORA-01990: error opening password file …

No password file

C:\> sqlplus / as sysdba
…
SQL> alter user sys identified by "iAmTheDBA!";
…
ORA-01990: error opening password file ''

SQL> select username, sysdba from v$pwfile_users;
…
no rows selected

C:\> '1AmThedba!' |
orapwd    `
   file=$env:ORACLE_BASE/database/PWD$env:ORACLE_SID.ora `
   sys=y

C:\> sqlplus sys/!amTheSysdba! as sysdba
…
SQL> alter user sys identified by "1amTheDBA,2!";

User altered.

See also