This error can be caused by a Windows PC going to sleep or standby mode. After the computer wakes up, it can no longer see the attached T.O.V.A. USB device. Furthermore, if the computer goes to sleep during an EAV test, the test will be interrupted and the results lost.

The first steps to fix and prevent this error are as follows:

1. Disable sleep mode on your PC. There are instructions for different OSes below.
2. Detach and reattach your T.O.V.A. device’s USB cable. It may take a minute for your computer to recognize the device again.
3. Exit and restart the T.O.V.A. software.

To be on the safe side, we recommend that you disable Sleep mode on any T.O.V.A. computer where you intend to do External A/V (EAV) testing. If that’s not possible, configure the computer to wait at least an hour before sleeping. There are other problems that can cause this error, so if you find that it occurs even after you perform these steps, or if it keeps recurring even after sleep mode has been disabled, contact T.O.V.A. technical support.

Note: How to disable Sleep mode on a given computer can vary somewhat. If the instructions below don’t work for you, contact your computer’s manufacturer.

Disabling Sleep mode on Windows 7

1. Click the Start button and type ‘Power’.
2. From the list that appears, choose ‘Power options’.
3. Select a new power plan if you want. For the selected plan, choose ‘Change plan settings’.
4. Under ‘Put the computer to sleep:’, choose ‘Never’. You may have to disable this in multiple places (‘Plugged in’, ‘On battery’, etc.).
5. Click ‘Save changes’.

Disabling Sleep mode on Windows 8

1. Bring up the Start page and type ‘Power’.
2. Click ‘Settings’ and then choose ‘Power options’.
3. Select a new power plan if you want. For the selected plan, choose ‘Change plan settings’.
4. Under ‘Put the computer to sleep:’, choose ‘Never’. You may have to disable this in multiple places (‘Plugged in’, ‘On battery’, etc.).
5. Click ‘Save changes’.

Disabling Sleep mode on Windows 10

1. Bring up the Start page and type ‘Sleep’.
2. Click ‘Power & sleep settings’.
3. Under ‘When plugged in, PC goes to sleep after’, choose ‘Never’.

Disabling Sleep mode on Windows 11

1. Bring up the Start page and type ‘Sleep’.
2. Click ‘Change when the PC sleeps when plugged in’.
3. Under ‘When plugged in, put my device to sleep after’, choose ‘Never’.

WARNING: Always plug in your laptop for the T.O.V.A. test. The test should never be administered on battery. Power loss during the test will likely result in loss of test results.