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Justin, Network Admin
Category: Mac
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Experience:  10+ years IT experience (Corporate Network Administration),
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When I try to copy and paste text between tabs in Mozilla Firefox,

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When I try to copy and paste text between tabs in Mozilla Firefox, I keep getting the error message -- "There is not enough memory or disc space to complete the operation".
I can copy and paste as normal in MSWord and other applications, but not in Firefox.
Any suggestions please?

Fairly common error, but not normally in Firefox. Possibly an add-on.

Let's try this first though. Right click Firefox, click Properties. Click the Compatibility tab. Are ANY of the boxes checked?

Customer: replied 4 years ago.

No - no boxes are checked.

Odd, alright.

I'd like you to right click the task bar (the bottom bar that goes across your screen part of windows).

Right click, click Task Manager.

Click Processes.

Locate Firefox.exe and tell me (next to it) how much memory it is using. It'd be listed like "xxx k"

Furthermore, on the bottom right of that window it should say "Physical memory" with a % number, I'd like to know that as well.

Customer: replied 4 years ago.

Firefox.exe - 220,532K


I cannot find "Physical Memory" in this window - the only % figure is "CPU Usage" which is fluctuating between 24% and 67%.


It also says "Commit Charge: 1080M/2460M.


It tells me that I have 59 Processes running - is this excessive?

The CPU is fairly high if you're not running any heavy duty programs (which I doubt you are).

That's why I'm thinking perhaps there is an add-in in Firefox that might be causing the issue. Though Memory usage of it doesn't look that bad.

Try this next, go to Tools > Add-ins.

Click Extensions on the left. Disable ALL of them.

Then go to Plug-ins on the bottom left. Disable those as well.

Restart Firefox, see if the symptoms remain. If they do not, we'll need to re-enable a few at a time. But start with Plug-ins. To save yourself time, do like 5-6 at a time and if the error returns, you know it was one of those.

Let me know the results of this test.

Customer: replied 4 years ago.

I've done that - I still cannot copy and paste between tabs, but I am no longer getting the error message, just nothing. I can still copy and paste between two MSWord documents, but if I try to copy and paste from Firefox into Word, I still get the error message.



I don't know whether this is relevant, but the computer has seemed generally very slow today. For instance, when I closed Firefox and restarted it, it took around 2 minutes to load.


(Also, I have just noticed the reference to 'Mac' at the top of this page - maybe I clicked a wrong button somewhere? I am not running a Mac, but a PC.)

You're in the right section, no worries there.

The symptoms could be related, for sure. Possibly something in your startup. Hard to root it out fully though.

We'll search for program conflicts (something is using a LOT of cpu). Do the following.

Go to start , click run. Type msconfig and hit enter. Click the startup tab. Uncheck ALL items listed here (this step is reversible as well should it have adverse effects).

Click apply, click ok. Restart the machine. Test Firefox again and the bootup speed should increase drastically. Post back results of both.

Customer: replied 4 years ago.

Have done this, unchecked all the boxes, but am now running out of time - have to go out!


I received the message "An Access Denied error was returned while attempting to change a service. You may need to log on using an Administrator account to make the specified changes."


I clicked "OK" and all the boxes appeared to remain unchecked - I now need to re-boot, which I'll have to do later, and I will get back to you.


Thanks for your help so far!



No problem, and that error is common and can be ignored (you'll notice the change goes through anyway).

Just reply to me later when you have time, there's no rush on this. I'm not ALWAYS here but I'll respond as soon as I can.
Customer: replied 4 years ago.

I have re-booted and a "System Configuration Utility" window appeared inviting me to choose 'Normal Startup Mode' which I ignored and continued.


I had to start Firefox manually and the problem remains. I will be out now until tomorrow, so will check in with you again then

No problem.

The error you get on restart is normal, it's just a warning, check the box, click OK and it will not appear again.

I would UNINSTALL firefox, then reinstall it. Use Internet Explorer for the time being until you reinstall firefox. During the uninstall,it shouldn't touch your bookmarks, if it asks to uninstall the bookmarks choose no.

You'll need your justanswer account setup to get back to me easily. Click my account on the top right, click edit password. set your password, click save changes.

Then, to return to me after reinstalling Firefox (or even to return to me via Internet Explorer), go to and click login at the top right, using email and the password XXXXX just created.

My Questions, should appear, and you can click our question name and see this screen again to reply to me.

Firefox install is located here:

Also, to remove Firefox. Go to start > control panel > add/remove programs. Find it in the list, and uninstall it from there.

Let me know the results when you are completed with these steps (tomorrow or whenever).

Customer: replied 4 years ago.

Hi Justin,


Boot-up was quite a lot faster this morning, but still I think not as fast as it used to be.


I have tried various 'cut and paste' tasks and this problem now appears to be solved.


Current status - (I'm sorry if I am flooding you with unnecessary info, but I don't know what is significant and what is not!!)


I have only Firefox, MSWord (1 small doc), MSExcel (1 small spreadsheet) and Windows Explorer running currently.


TASK MANAGER tells me that Firefox usage is 184,560K - Processes 37 - CPU Usage varies 0 - 25% - Commit Charge is 694M/2460M.


I have not yet re-checked my Startup items in System Config Utility - (I am surprised to see that there are 35 items listed here - is this a lot?)


I have not yet restored Firefox extensions (10 items) nor have I restored plugins (19 items).


Would you still recommend that I uninstall and reinstall Firefox before doing any of the above? I am reluctant to do this unnecessarily as I had big problems a while ago when McAfee told me to uninstall and reinstall their software - after an update, their software had totally blocked my internet access and I had to get an engineer to come and restore all the settings on my wireless router (at great expense!)


I understand what you said about re-enabling Plugins and extension a few at a time to see if the problem recurs, but in what order should I proceed with all of the above?


Kind regards, pB

Nothing totally seems out of the ordinary there.

The newer versions of Firefox tend to be a bit more resource heavy. Though an uninstall/reinstall won't really hurt Firefox, it's probably unnecessary at this point.

Some other program in the startup was causing the issue, though besides through trial and error it's very difficult to determine which one It happens though, it's good to keep a clean startup and only running programs when you need them, not on windows boot.

If you need anything further don't hesitate to reply. If you're all set, please don't forget to rate my assistance below (using the smiley's). Tips are appreciated but not required. Thank you very much.
Customer: replied 4 years ago.

Hi Justin,


I'm sorry not to have replied before now - I had to go away unexpectedly last week to look after my Grandchildren while my daughter was in hospital following a car accident. All is well again now, thankfully!!


I have not yet 'rated' your service, although I am very pleased with your assistance and will certainly be giving you 5 stars. There are just a couple of points on which I need some clarification, please.


My original problem seems to be resolved, although my system still seems very slow to 'boot up'.


Windows Task Manager currently shows:- Only 2 Applications running, but 51 Processes running. (I can email you a screenshot of the list if this would help.) CPU Usage is between 2% and 24%. Commit Charge: 966M/2460M. Firefox is using 165,540K.


I have re-checked the Firefox Plug-ins and Extensions which I recognise, and also the Startup items which I know that I require. I have left 17 Startup items unchecked, as I do not recognise them as items which I need.


Under Firefox Plugins, there is a warning that MetaStream 3 has been disabled due to Security or Stability Issues - could this have been causing my problem? I am uncertain about whether I need to recheck the following: Microsoft DRM (which appears twice on the list!), Silverlight Plugin 4.1.10329.0 and Windows Presentation Foundation 3.5.30729.1 ?


Under Firefox Extensions, I don't know whether I need to recheck Microsoft .NET Framework Assistant 0.0.0 ?


I don't know what these items do - can you advise, please?


With kind regards, pB

I'm glad everything is ok, and no problem on the delay. There's no rush here. I'm unfortunately out this evening but can address your concerns tomorrow if you're available, or any day following. Just toss me a reply when you're available and I'll take care of it. Thanks
Customer: replied 4 years ago.

Thanks Justin - I'll contact you tomorrow (Sunday), but not sure where you are and what time-zone you are in! I am currently in France (GMT +1).



Firefox is fine, ignore the entries on all accounts, nothing needs to be reenabled until firefox prompts you to use them in which you can reenable them when asked. But I doubt it wil.

As far as speed, after changing the msconfig, only most likely causes would be a virus, or the antivirus itself.

Download this program, do a system scan.

If it finds and infection, click Show Results and then click Remove Selected once the scan completes. Restart if prompted.

If there's still no speed improvement, try uninstalling your antivirus, then reinstalling it or installing a different/faster one, like Avast
Justin and 7 other Mac Specialists are ready to help you
Customer: replied 4 years ago.

Hi Justin,


Following our last communication around 3 weeks ago, when I thought that we were done and I 'rated' your answer, I tried many times to get back to you, but each time I just saw a blank white screen and I had given up. However, yesterday I received a follow-up email, so have tried again and seem to have made contact this time!


Although my original problem was solved it soon became apparent that in solving this I had acquired some new problems. I went to one of the links which you suggested and downloaded a trial version of 'Malwarebytes' anti-virus and was initially impressed that it was blocking access to potentially malicious website. However, I was receiving these 'pop-ups' incessantly with a new one appearing as soon as I had closed one - sometimes there would be 8 or 9 on top of one another. As well as this, everything had slowed to a crawl and every time I booted up my McAfee anti-virus had been disabled and I had to re-enable it.


Booting-up was (and still is) very slow, with the system regularly 'hanging up' with the hourglass symbol. If I open, for instance 'MSWord', it takes forever, with the whole system appearing to freeze for a couple of minutes or more. When I click to close a window, instead of just disappearing it clears gradually by 'scrolling' down the screen, taking 30 or 40 seconds and then leaving the 'outline' on top of the window behind it, rendering it unusable, for another minute or so.


I soon realised that the multiple 'Malwarebytes' pop-ups were a constantly repeating rotation of 7 specific I P addresses, 6 of which I tracked down to "" and the 7th to "".


I tried closing Applications one at a time in Task Manager to identify which application was responsible. Eventually I had close all the listed applications and still the pop-ups continued - even then, with only Firefox running Task Manager showed CPU usage fluctuating between 29 and 100% and with Firefox closed it was between 22 and 96%.


I became so frustrated with this that I tried to delete Malwarebytes but found that I was unable to do so. Unable to get back to you, I could only wait until my trial time expired, but now I get constant pop-ups telling me that it has expired and that I should subscribe - still I seem to be unable to delete or uninstall it.


At the moment, everything is really slow with repeated 'hour glass' hang-ups lasting anything up to 3 minutes. Sometimes it hangs up permanently on boot-up or while shutting down and I have to pull the plug and re-boot. Whilst writing this message I have had to close 6 Malwarebytes pop-ups reminding me to subscribe.


Currently CPU usage is 100% with just Firefox and a McAfee background scan running.


Can you help? pB

You still likely have some sort of infection or typical Mcafee having issues (ha)

And honestly, mcafee is one of the worst AV's out there and could be part of the problem.

In fact, if I had to guess right now, I'd say it IS the problem (using all the CPU). You'll have to just take my word for it at this point, but I would start with removing Mcafee via start > control panel > programs (if it even lets you). Then we'll troubleshoot from there.

We need to get that cpu usage down. If it doesn't help after the removal of mcafee, I will give you some advanced steps following your reply. Sorry you had so much trouble getting back.

Customer: replied 4 years ago.

Hi Justin,


I tried to get back to you yesterday, but my Internet connection was down for whatever reason - maybe related to my problems but possibly just a coincidence! I was short on time so couldn't pursue it yesterday, but it's up and running now, after a fashion!


I have taken on board what you say about McAfee - I guess that if this is the cause of the high CPU usage it explains why everything else is proceeding at a snail's pace.


However, the last time I had an issue with McAfee, their advice and my attempts to sort it resulted in the total loss of communication between my computer and the wireless router which left me totally helpless and at the mercy of a very costly home-visit 'tech help' engineer, who had to interrogate and re-establish the settings on the router.


I have a lot of work to get through in the next few days for which I need to retain my internet/email access, albeit very slow and time-consuming - so I'm reluctant to attempt to remove McAfee right now for fear of repeating this situation. Once I'm up-to-date with this work and can better afford to 'take the risk' I will do so and hopefully I'll contact you again.


In the meantime, I am still getting the 'Malwarebytes' popups - should I try again to remove this program?


Many thanks for your continued support. With kind regards, pB



Malwarebytes is legit.

As for Mcafee, after removal, run the Mcafee removal tool after. Just download it and save it somewhere you can remember it.

The link above should be the tool. Let me know how it goes when you have time.