Can a technician access my PC at any time?

Solution 1:

Can my technician access my PC when it is turned off?

Not without your permission initially.

In general, it is only possible to access your computer if you share your TeamViewer ID and the associated random password with another person. Without knowing the ID and password, it is not possible to access your computer.

Warning:

It is possible to set up unattended access which gives anyone with the username and password unattended remote access to another computer.

To remove unattended access

• Menu Extras >> Options >> Security >> Personal password (for unattended access) >> (remove both)
• Menu Extras >> Options >> Advanced >> Show advanced options >> Random password after each session >> set to Generate new (instead of the default Keep current)

Nobody can now connect without you giving them the new random password.

If you are not running the TeamViewer client (or service) on your computer remote access is not possible at all.

To completely prevent any access with ID and password, exit TeamViewer in the taskbar.

How can I restrict access for TeamViewer connections to my computer?

In general, it is only possible to access your computer if you share your TeamViewer ID and the associated random password with another person. Without knowing the ID and password, it is not possible to access your computer. Do not share your ID and password with a person you do not trust.

You can also restrict access to your computer in different ways. Depending on how you want to restrict access and to what extent, choose one of the following options:

• To completely prevent any access with ID and password, exit TeamViewer in the taskbar.

  Any incoming or outgoing connections are no longer possible.

• To restrict access to ordained devices, use the Black- or Whitelist in the TeamViewer full version.

  Deny incoming connections for specific TeamViewer IDs or only allow connections for defined TeamViewer-IDs.

• To restrict features for incoming connections, use the access control for incoming connections.

  Choose between Full access, Confirm all, viewing access or deny any incoming remote control connection.

• To deny connections from outside your network, only allow incoming LAN connections.

Source TeamViewer FAQ

Solution 2:

It depends on how the person who installed it set it up.

Open TeamViewer and look at how the Access Control setting are configured.

• Click on Extras menu, click Options and then click Advanced.
• In the right-side pane, scroll-down to see Advanced settings for connections to this computer.
• Select Custom Settings from the drop-down box and then click the Configure button to launch Access Control Details dialogue.

More info/step source

Also, TeamViewer site is an excellent resource for information about TeamViewer.

For example: How can I restrict access for TeamViewer connections to my computer?