What would cause a slim horizontal line across the screen of my iMac?

There is a slim line across the Center if the screen. It is horizontal. It does not appear every time I boot up, but it is causing concern.

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It would mean that your display or GPU are starting to fail, most likely the GPU, as the line is not permanent. Does the line move during the time your iMac is turned on or change if you start up in safe mode (holding the Shift key while your Mac is starting)?
A good test you can do is to make a screenshot of the screen when your iMac is showing the line. To make the screenshot, press Command, Shift and 3 keys, and the screenshot will appear in the desktop. Double-click it and see if the line appears. If it appears, it's the GPU. If not, it's the display

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Horizontal lines across the screen of my Vision:M, need he

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Flickering horizontal lines across the screen

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I have a horizontal line across the middle of the ipod screen and the ipod and itunes won't sync. What is the line and is it connected to the no sync.

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Horizontal line across the monitor. It happened yesterday.

I have a HP ENVY 23-c1 10xt AiO (Lavaca3-SB)PCUS and there is a horizontal line across the monitor. It happened yesterday.

Hello again javajohn23,
I would like you to try the following steps:
Step 1. Turn off the computer, and then remove the power cord
Step 2. With the power cord disconnected, press and hold the power button for five seconds
Step 3. Reconnect the power cord, and then turn on the computer
If the above steps do not resolve it try the next set up steps:
Step 1. Restart your computer
Step 2. Repeatedly press the F10 key about once every second for five seconds after turning the computer on
Step 3. Wait five seconds
Step 4. Press the F5 key. This restores the default settings of the BIOS
Step 5. Press the Enter key. This accepts the changes
Step 6. Press the F10 key. This opens the Save and Exit window
Step 7. Press the Enter key. This saves the changes, exits the BIOS, and then the computer restarts
Step 8. Restart the computer.
Another thing I can think to try is review the HP Support document: Changing Display Settings, Background Image, Icons, and Screen Saver (Windows 7) to see if you can identify anything out of place.
We can also try to reload the Intel Graphics Driver for your computer as it will wipe out the settings when the new driver is reinstalled.
Please re-post with the results of these steps. Thank you for posting on the HP Forums. Have a great day!
Please click the "Thumbs Up" on the bottom right of this post to say thank you if you appreciate the support I provide!
Also be sure to mark my post as “Accept as Solution" if you feel my post solved your issue, it will help others who face the same challenge find the same solution.
Dunidar
I work on behalf of HP
Find out a bit more about me by checking out my profile!
"Customers don’t expect you to be perfect. They do expect you to fix things when they go wrong." ~ Donald Porter

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Hi @Sillenn
Welcome to the HP Forums!
I would like to take a moment and thank you for using the forum, it is a great place to find answers. For you to have the best experience in the HP forum, I would like to direct your attention to the HP Forums Guide First Time Here? Learn How to Post and More.
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Sparkles1
I work on behalf of HP
Please click “Accept as Solution ” if you feel my post solved your issue, it will help others find the solution.
Click the “Kudos, Thumbs Up" on the bottom right to say “Thanks” for helping!

They are dotted lines across the screen horizontally.

When I upgrading to Lion Mountain, now I see somes "Drops" in the images. They are dotted lines across the screen horizontally. I reformatted and reinstalled OS 10.8.2, but the problem persists. I went to service, thought it was a video card problem, but it was not.

I have this too! I just bought this iMac a few months back. These screen are having a lot of troubles from what I am reading. My horizontal lines are not that bad, but you can notice them.
I might sell these computer off quick as apparently the quality of these screens is a nightmare.

I have a straight horizontal line across my screen

Hi Folks
have a straight horizontal line across my screen. Can assist?

Yes, move the screen slowly back and forth, if it changes, you have a damaged monitor feed cable
Does it appear in all screens?
Does it vanish from time to time?
post a pic, hook your AIr up to an external monitor, if its there, its GPU /logic problem
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perform SMC reset and re-verify
SMC reset
Shut down the computer.
Plug in the MagSafe power adapter to a power source, connecting it to the Mac if its not already connected.
On the built-in keyboard, press the (left side) Shift-Control-Option keys and the power button at the same time.
Release all the keys and the power button at the same time.
Press the power button to turn on the computer.
Note: The LED on the MagSafe power adapter may change states or temporarily turn off when you reset the SMC.
Contact Apple for an appt. for in shop diagnostics and likely repair.

I have a horizontal line across the bottom of my screen how do I remove it?

Re: Macbook Air mid 2011, I have a horizontal line across the bottom of my screen, it appeared when I was updating my iPhone, How can I remove this line from my display?

It may be a GPU or display issue. In both cases, make a backup of your Mac and take it to an Apple Store or reseller to get it repaired.
To check whether it is a GPU or display issue, try taking a screenshot by pressing Command, Shift and 3 keys. The screenshot will appear in the Desktop, so open it and check if the line appears in the screenshot too. If so, it is a GPU issue; if not, it is a display issue.

Lines across the screen

I have noticed for the first time today (after I have been working on my iMac for a long time) that there are horizontal lines across the whole screen from the top to the bottom. First I thought they would only be on the picture of my desktop background, but then I opened iPhoto and saw the lines on every picture I opened. So those lines are there on the screen and and not only on the displayed image. Really annoying!!!
Unfortunately my iMac is not under guarantee anymore...

I have this too! I just bought this iMac a few months back. These screen are having a lot of troubles from what I am reading. My horizontal lines are not that bad, but you can notice them.
I might sell these computer off quick as apparently the quality of these screens is a nightmare.

Issues with lines across the screen, as well as freezing

Issues with lines across the screen, as well as freezing
Hello all
Got an iMac since January 2008 and I do like it a lot, even though it has some issues:
-- It displays (quite often) lines partially across the screen
-- Lines appear as well when opening applications or when menus come up
-- The system freezes more than I like to admit (more than my Windows/Ubuntu box)
I don't know if the freezing has to do with the lines that are shown on my screen. But I assume that both issues relate to some video card problem. I can't be sure - but that's what I assume from living with this issue day to day.
The line on the desktop (most of the time it is there before login) I can always get rid of by changing the display resolution to something else and then changing it back. Normally the line is gone, or, reappears on a different spot on the desktop. But repeating the procedure removes the line.
However, this does not mean that the lines are not showing up again when launching apps or displaying menus!
And since those lines appear to happen randomly, I think it's safe to assume that we're not talking dead pixels here, either...
About the freezing:
My iMac freezes sometimes when I move the mouse around, when switching desktops using "spaces" or when the zoom function of the Dock kicks in. Sometimes the screen goes completely black, sometimes completely white. The mouse, however, always works. But the system requires a reboot.
Again, this happens too often to feel comfy about it.
With my little knowledge of Mac troubleshooting I assume that there's something wrong with the ATI card that's built into my Mac. On the other hand, some people say that they started getting similar issues after updating their OS to Leopard. Again other people say that such issues stem from an ATI revision that is too old and the Mac should get a new ATI card. And how would that work? Isn't that an "all-in-one" machine with everything soldered onto the mainboard?
So, any help in this matter is greatly appreciated...
Cheers,
Rainer

Here are a few screen photos I've taken (not screenshots, as the lines are not visible when taking screenshots. I used my digicam to snap those...).
Here's the link to those screen photos displaying some of the many lines I keep having:
http://picasaweb.google.com/rainer.rohde/NewAlbum62508115AM
Needless to say, as I typed this message here, I had a nice line going across my Safari window..
Cheers,
Rainer

My phone switches off after showing horizontal lines on the screen during the restore process and then shows the error 9 problem. please help i am so stressed.

Hello
My iphone 4S switches off after showing horizontal lines on the screen cutting through the apple logo during the restore process and then right after my iTunes shows the error 9 message, this happened 2 days ago when my phone just switched off unexpectedily and has been in this recovery mode since then. i have watched videos on Youtube and i have disabled Firewall before starting the process, i think i have done almost everything. please help anyone what do i do from here?
Just for interest sake i watched this video on youtube where this guy had the same problem but the difference is that he had it on an iPad. he opened the ipad up and did something on the ipad, it took less than a minute then his ipad worked.
I would appreciate it if someone would respond to this as fast as they can i am so stressed.
Regards
Lwando

Read here:
http://support.apple.com/kb/ts3694#9
Error 9 is usually a security software issue.

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Hey everyone!
So, I have recently dropped my iPhone 4S and now there are all these blue vertical lines across the screen, which occasionally change colour also.
I am still able to receive messages and calls, and siri still works, it's simply that I can't see a single thing I am doing- which is very difficult!
I was wondering if this is an issue that needs to be fixed at an Apple store- and if so, how much it would cost? Or if I would be able to fix it myself somehow.
N.B: I've tried to reset it, it doesn't work. I have also tried to restore the iPhone, but iTunes won't let me do this as I have to have the 'find my iPhone' app turned off, which I cannot do because I can't see anything I'm doing!
Thanks in advance for any help/suggestions,
Kirstoodles.

Kirstoodles wrote:
I was wondering if this is an issue that needs to be fixed at an Apple store- and if so, how much it would cost?
Yes. It's broken. A replacement will cost you $199.
Or if I would be able to fix it myself somehow.
The iPhone is not user servicable. Apple does not sell parts for the iPhone. any parts you could get are either stolen, counterfeit, or salvaged. Atempting to fix it yourself will render it unsupportable and forfeit your right to service from Apple, including an out of warranty replacement.

How do I fix lines across the screen while on web pages?

I am getting lines across the screen on my Mac Book Pro. This is while I am on a web page. How do I fix this?

Those don't look like classic signs of hardware issues.
Of greater concern, I notice that you have both Trend Micro and MacKeeper installed. It's generally a bad idea to have two different anti-virus programs installed at the same time, as any active scanning each does can conflict with the other.
MacKeeper is very bad software, made by unethical developers in Russia. You should uninstall it immediately. See:
http://applehelpwriter.com/2011/09/21/how-to-uninstall-mackeeper-malware/
As for Trend Micro, note that its detection of Mac malware is not particularly good. See:
http://www.thesafemac.com/mac-anti-virus-testing-01-2013/
I would recommend uninstalling it as well. You should find an uninstaller in the Trend Micro folder in your Applications folder. If uninstalling all your anti-virus software makes you nervous, see my Mac Malware Guide. If you decide to install some other anti-virus software, use one recommended by that guide.
Back to the line problem, if uninstalling those programs doesn't help, try some browser other than Chrome (like Safari). Do you see the same problem there, or is it only happening with Chrome?

A few months back I Dropped my iPhone 4 and I cracked my screen and now i cant unlock my phone due to touchscreen not working plus there are blured lines across the screen and I can't see anything that it displays. Now when I try too connect my iPhone 4 t

A few months back I Dropped my iPhone 4 and I cracked my screen and now i cant unlock my phone due to touch screen not working plus there are blurred lines across the screen and I can't see anything that it displays.
Now when I try too connect my iPhone 4 to iTunes on my computer at home an error message comes up saying that I have to unlock my iPhone 4 for it to communicate to my device.
But the problem is that I can't unlock my iPhone 4 because I'm unable to see the key pad and my touch screen no longer responds when I touch it.
I just want to reset my iPhone 4 back to its Factory Settings & start all over from the beginning.
How can I unlock my iPhone 4 with iTunes on my computer or any other option you suggest me trying.
Thank you in advance,
SiHero

If you have had a "local guy "repair your iphone you will not get any support from Apple for warranty OR post warranty
If Verizon return it to Apple it wil not be handled by Apple
If Verizon also use unauthorised repairers you may be lucky
(Apple do not sell parts to local guys or anyone else )

What would cause a slim horizontal line across the screen of my iMac?

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