Hello:

I'm using Excel 2010 and when I try to open several workbooks a message "Excel cannot complete this task with available resources. Choose less data or close other applications" appears.  This happens when I open email attachments from MS Outlook and files on my C-Drive.

Thank you for your help

Hello,

did this just start to happen? Did it use to work? How big are the files? How much memory does the computer have available. What else is running in the background? Does it happen when the machine has just been booted?

Try with a freshly booted machine and with Excel in safe mode, so it does not load any add-ins. If that helps, the add-ins may be the problem. 

Hi NFL1,

Could you tell me which version of office are you using, 32bit or 64bit? You said this issue always happened when open attachments from outlook and files in C-Driver.

For opening attachments from outlook, it might there is a conflict between the preview pane and Excel. You can try to hide the preview pane as a workaround to solve this issue. Please refer to this link:
https://support.microsoft.com/en-us/kb/2526883

It is often the case, if your file is large or contains a large amount of features, it is possible you are running low on available memory resources. If you work with extremely large data sets, the 64-bit version of Office may perform better for you. 32-bit office you run are limited to making use of only 2GB of RAM. And this is one of the reasons occur the issue, you can via these links to get more information about this issue and detailed methods to solve this problem.

https://support.microsoft.com/en-us/kb/2779852

http://blogs.technet.com/b/the_microsoft_excel_support_team_blog/archive/2012/05/22/quot-excel-cannot-complete-this-task-with-available-resources-quot-after-installing-ms12-030.aspx

Please try these methods and let me know if they work, I am glad to help and forward to your reply.

Regards,