ORA-01654: unable to extend index in tablespace SYSTEM

Run this:

select db.FILE_NAME, db.AUTOEXTENSIBLE, db.INCREMENT_BY, db.USER_BLOCKS,
t.INITIAL_EXTENT, t.NEXT_EXTENT, t.EXTENT_MANAGEMENT
FROM dba_data_files db, dba_tablespaces t
where db.TABLESPACE_NAME = t.TABLESPACE_NAME;


I get this:

"FILE_NAME" "AUTOEXTENSIBLE" "INCREMENT_BY" "USER_BLOCKS" "INITIAL_EXTENT" "NEXT_EXTENT" "EXTENT_MANAGEMENT"
"C:\ORACLEXE\ORADATA\XE\USERS.DBF" "YES" 1280 12792 65536 "LOCAL"
"C:\ORACLEXE\ORADATA\XE\SYSAUX.DBF" "YES" 1280 61432 65536 "LOCAL"
"C:\ORACLEXE\ORADATA\XE\UNDO.DBF" "YES" 640 52472 65536 "LOCAL"
"C:\ORACLEXE\ORADATA\XE\SYSTEM.DBF" "YES" 1280 76792 65536 "LOCAL"


So I do
alter database datafile 'C:\ORACLEXE\ORADATA\XE\SYSTEM.DBF' resize 3500M;

( on Widows, the max filesize must be 4GB, I guess)

and you get a confirmation
"database datafile 'C:\ORACLEXE\ORADATA\XE\SYSTEM.DBF' altered."