What causes this error?

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Level 1

11 points

What causes this error?

I get this error every couple of weeks. This completely defeats the purpose of running Time Machine. Anybody know what might cause this error?

My setup is a Mac 21.5" running OSX 10.7.3 connected via WiFi to an Airport Extreme (firmware v7.6.1). The Airport Extreme is connected via Ethernet-cable to a Synology DS411j (DSM 4.0) on which the Time Machine sparsebundle resides. Another Mac also uses the SAN for Time Machine backups and hasn't had any troubles sofar.

iMac, Mac OS X (10.7.3), 2.7GHz Core i5, 8GB

Posted on Mar 31, 2012 12:45 PM

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Answer 1

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LaPastenague

Level 9

67,208 points

Mar 31, 2012 1:30 PM in response to Mausy

See the info here.

http://pondini.org/TM/C13.html

Open the airport extreme and look at the logs.. see if the wireless has experienced dropouts..

Although the problem is not Lion/wireless/7.6.1 combo per sec.. that is not infrequent result. The backup can end up corrupted and fails the checks.

Is the other computer without issues SL not Lion?

Or uses ethernet not wireless.

If you cannot connect by ethernet to the computer that has trouble, try setting the AEBS to manual wireless settings.

Change all names .. ie the AEBS itself and the wireless name (SSID to everyone but apple) to a short name, no spaces no special characters, ie pure alphanumeric. Different name also no spaces for 5ghz.

Change wireless mode to a/n-b/g manual.

Change channel to manual.

Test using channels 1, 6, 11.

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Answer 2

Mausy Author

Level 1

11 points

Apr 8, 2012 7:46 AM in response to LaPastenague

LaPastenague wrote:

Open the airport extreme and look at the logs.. see if the wireless has experienced dropouts..

With the new Airport Utility there is no obvious way to get to the logs. So, no info from them.

Is the other computer without issues SL not Lion?

Or uses ethernet not wireless.

It's next to the Extreme so its connected via wire , as is the SAN.

Change all names .. ie the AEBS itself and the wireless name (SSID to everyone but apple) to a short name, no spaces no special characters, ie pure alphanumeric. Different name also no spaces for 5ghz.

Change wireless mode to a/n-b/g manual.

Change channel to manual.

Test using channels 1, 6, 11.

The 5GHz network is named the same as the SSID except it has "<space>5GHz" behind it.

Never thougth of naming it differently. I'll try that. Could a '.' in the name be a problem?

BTW, does that mean I'll have two networks?

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Answer 3

Apr 8, 2012 12:58 PM in response to Mausy

Download and use 5.6 utility for Lion.. v6 in Lion can run alongside 5.6 to provide pretty network pictures.

http://support.apple.com/kb/DL1482

You will want to download your local version in Dutch??

So the cabled computer has no problems.. definitely a wireless issue then.

Could a '.' in the name be a problem?

Yes, if you are going to fix names fix them properly. No spaces no non-alphanumeric.. it is not that some special characters cannot be used.. it is to reduce the chance of problems. Wireless names (SSID) does not contribute to security at all.. except that it is good to use a name different to standard. ie if all brandx modems and routers use wireless name brandx it allows people to precompile lists of brute force attack. If the name is different they need to create it on the spot.. but in neither case is it a big issue.

I name the TC.. TC3 for example.. call the 2.4ghz wireless TC24ghz and the 5ghz TC5ghz. Just use something that makes good sense to you so you can identify it as your signal not your neighbours.

BTW, does that mean I'll have two networks?

No both 2.4ghz and 5ghz will share the same ip range and can talk to each other.

It is just like having two different ethernet cables. The problem with wireless, is it is single channel half-duplex.. and like the old thin ethernet, everybody shares the same band.. and divides the bandwith. Using two different bands allows two computers to talk at the same time.

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