title: Can't start / connect to Oracle Database - Windows 10 / Oracle 18 XE / SQL Developer
body: <p>I am trying to install and run this database for a week... ;&lt; 
  I previously tried with Oracle 12 c standard edition but it didn't work - I don't know why ;( 
  For now I have uninstalled (I believe) the 12 c and installed 18 XE..</p>
  
  <p>On SQL Plus I have: ORA-12560: TNS:protocol adapter error service is running when I try to log in as sysdba</p>
  
  <p>All services on services.msc are running:
  - OracleOraDB18Home1MTSRecoveryService
  - OracleOraDB18Home1TNSListener
  - OracleRemExecServiceV2
  - OracleServiceXE
  - OracleVssWriterXE</p>
  
  <p>On command line when I type "lsnrctl status" I have:</p>
  
  <pre><code>Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=DESKTOP-*******)(PORT=1521)))
  STATUS of the LISTENER
  ------------------------
  Alias                     LISTENER
  Version                   TNSLSNR for 64-bit Windows: Version 18.0.0.0.0 - Production
  Start Date                23-NOV-2019 10:41:47
  Uptime                    0 days 11 hr. 36 min. 34 sec
  Trace Level               off
  Security                  ON: Local OS Authentication
  SNMP                      OFF
  Default Service           XE
  Listener Parameter File   C:\app\*****\product\18.0.0\dbhomeXE\network\admin\listener.ora
  Listener Log File         C:\app\*****\product\18.0.0\diag\tnslsnr\DESKTOP-*******\listener\alert\log.xml
  Listening Endpoints Summary...
    (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=DESKTOP-*******)(PORT=1521)))
    (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(PIPENAME=\\.\pipe\EXTPROC1521ipc)))
  Services Summary...
  Service "CLRExtProc" has 1 instance(s).
    Instance "CLRExtProc", status UNKNOWN, has 1 handler(s) for this service...
  The command completed successfully
  </code></pre>
  
  <p>And on SQL Developer I have one of 2 errors, depending what I write there: 
  - Status : Failure - The Network Adapter could not establish the connection
  - Status : Failure -Test failed: Listener refused the connection with the following error:
  ORA-12514, TNS:listener does not currently know of service requested in connect descriptor</p>
  
  <p>I don't know what I am doing. I just want to install and run this as quickly as possible to practice on sample database for an exam :( This is my PC, no virtual machines or online servers</p>
  
  <p>Please help me investigate the issue - I checked several answers, even on this site, but I can't understand them well, there are a lot more information there than I need....</p>