Why do some Excel processes fail to terminate after using XLSREAD, XLSWRITE or XLSFINFO in MATLAB?

When I use a command that calls Excel as an ActiveX server, such as XLSREAD, XLSWRITE, or XLSFINFO, an Excel.exe process is left in memory even after the command is finished or I close MATLAB. If I am running a script with many calls to XLSREAD, the ghost processes fill up my memory.

Answer 1

[MathWorks Support Team]

As of R2015b, this issue has been resolved as MATLAB will now only open one instance of Excel for a file and does not attempt to close it after the call.

Previous to R2015b, in some circumstances Excel may not shut down after calling XLSREAD, XLSWRITE, or XLSINFO from MATLAB.

Whenever one of these commands is executed in MATLAB on Windows and Excel is installed, a new instance of Excel is started to perform the operation using Excel's ActiveX interface. After the operation is completed, MATLAB requests that Excel quit, however in some circumstances, Excel may ignore this request.

One reason this may occur is if some other application has established an ActiveX connection to Excel and is hanging on to a reference to the interface, and not releasing it. The way ActiveX works is that if 2 applications both make connections to the same server, the server will not close until both applications have terminated their connection. The connection from MATLAB is being terminated, however it is possible that another application has made a connection to Excel. In the past we noticed an issue where Google Desktop Search would create such a connection, however starting with MATLAB 7.0.4 (R14SP2) this issue was resolved by working around the specific way that Google Desktop Search made its connection. If you are experiencing this same issue with a later version of MATLAB, or do not have Google Desktop Installed, there is likely another application on your computer which is holding on to the Excel application ActiveX reference.

One way to work around this issue is to identify the application that is causing this issue, then disable it. You can also contact the company which created the software to notify them of this issue.

Certain Excel add-ins may also prevent proper termination of Excel. Some known add-ins that might cause issues are Broadcom's "Send to Bluetooth" add-in (btsendto_office.dll) and Bloomberg's TaskpaneHost add-in. Disabling the add-ins that cause issues is a possible workaround.

When you use a Bloomberg add-in, that causes this issues: Please open a help chat (by pressing the help key twice on the Bloomberg keyboard) and ask for the technical departement. Bloomberg will then have a look into these issues.

As a last resort you can use the SYSTEM command via MATLAB to kill the process.

system('taskkill /F /IM EXCEL.EXE');

[Jeffrey Girard]

I have also had this problem when running CSVWRITE within a loop, leading to there being dozens of EXCEL.EXE processes running. The last resort option worked and its inclusion in this answer was appreciated.

[Juan Chilla]

I started having this problem recently, when the IT department upgraded us to Office 2013. It appears Matlab's request to close Excel is not properly implemented for the new(er) version of Excel. The workaround I found is to add a "clear functions" command for Matlab to properly close the ghost process.

[Image Analyst]

Starting with R2015b, Excel does not shutdown after calls to xlsread() or xlswrite(). However there should be only one instance running:

http://www.mathworks.com/help/matlab/release-notes.html

Data Import and Export

Excel Spreadsheets: Read and write to the same spreadsheet repeatedly with improved performance of xlsread, xlswrite, readtable, and writetable functions

Repeated calls to the xlsread, xlswrite, readtable, and writetable functions show significant performance improvement.

[Ye Chen]

same problem with matlab 2014b 8.4.0.150421 (64-bit) on win 7 and office 365. no mentioned interfering programme installed. the 'last resort' works. Also, after upgrade to 2015b, it disappeared. thanks.

[Jan]

Moved from a flag of lux :

it's very helpful, tks

@lux: Please use flags only to inform the admins and editors about contributions, which might collide with the terms of use e.g. by rudeness. Thanks.

[Matt]

Matlab 2016a this is happening with Excel Professional 2013. In an odd twist all other Excel instances opened are locked into not warning when exiting with changes. Killing the tasks is not good because there could be unrelated Excel instance that will close without prompting to save changes...losing work. Closing all instances of Excel and then reopening reverts Excel back to normal, prompting saves when exiting with changes.

[Dima]

This is not a working solution - this code terminates all instances of Excel -we are runnign loop with excel link - we need the master excel life to stay active - can this be done? keep the first looping excel process active and kill all excels opened by Matlab??

Answer 2

[Daniel Atanasov]

Hey guys, I had to solve this problem myself somehow without killing all open Excel processes but only the ghost ones. I wrote this code that just gets the IDs of all Excel processes before and after xlsread or xlswrite with strfind() and deletes the new ghost ones with taskkill. Sorry for the bad code, but I hope it helps.

[~,tasks] = system('tasklist/fi "imagename eq Excel.exe"');
   tasks=sscanf(tasks,'%s');
   exe=strfind(tasks,'.EXE');
   console=strfind(tasks,'Console');
   pid_before=zeros(1,size(exe,2));

      for i=1:1:size(exe,2)
          pid_before(1,i)=convertCharsToStrings(tasks((exe(i)+4):(console(i)-1)));    
      end

      %Your xlsread/xlswrite code

         [~,tasks] = system('tasklist/fi "imagename eq Excel.exe"');
         tasks=sscanf(tasks,'%s');
         exe=strfind(tasks,'.EXE');
         console=strfind(tasks,'Console');
         pid_after=zeros(1,size(exe,2));

        for i=1:1:size(exe,2)
            pid_after(1,i)=convertCharsToStrings(tasks((exe(i)+4):(console(i)-1)));    
        end

        if size(pid_after,2)>size(pid_before,2)
            command=['taskkill /f /PID ',mat2str(pid_after(1,end))];
            system(command)
        end

[Dima]

will it work in matlab 2011?

[Walter Roberson]

No. convertCharsToStrings did not exist before R2016b. The closest you could get is to use pid_before{1,i} = tasks((exe(i)+4):console(i)-1)));

[Dima]

can you please help me? Can you provide the full code which will work in matlab 2011? thanks a lott!

[Dima]

sweet - let me try it

[Dima]

I got this error in matlab:

Line, 17:06
Undefined function 'strsplit' for input arguments of type 'char'.

Error in indicatorsOUTblack2 (line 2)
list       = strsplit(tasks, char(10));
 

[Guillaume]

You're going to have to look through the documentation of recent versions, find out what all the functions that you are missing do and reimplement them somehow for your version. I doubt many people are still running R2011, it's now 8 years out of date.

Or upgrade to a version not as antiquated

Or as I keep saying not worry about excel processes. The browser you're using to ask the question probably uses more memory and ressources than the ghost excel process.

For strsplit, you can probably replace it by

list = regexp(tasks, char(10), 'split'); %probably works in R2011

[Jan]

@Dima: Sorry, I did not want to post this code. This was a mistake. I do not have the time today to post a working solution, maybe at the weekend.

Remember that calling taskkill of the OS is a killer. It can destroy work efficiently.

[Dima]

thank you Jan - maybe you can do this on weekend?

[Walter Roberson]

In the original code, change convertCharsToString() to be str2double()

[Dima]

thnaks - I HAD A SHORT QUESTION -apart from xlread I have 1000 lines of code - shoudl these also be placed in the middle of this scrip?

[Dima]

I tested this scrip (I am using Matlab R2011b):

[~,tasks] = system('tasklist/fi "imagename eq Excel.exe"');
   tasks=sscanf(tasks,'%s');
   exe=strfind(tasks,'.EXE');
   console=strfind(tasks,'Console');
   pid_before=zeros(1,size(exe,2));
      for i=1:1:size(exe,2)
          pid_before(1,i)=str2doubles(tasks((exe(i)+4):(console(i)-1)));    
      end
      %Your xlsread/xlswrite code
         [~,tasks] = system('tasklist/fi "imagename eq Excel.exe"');
         tasks=sscanf(tasks,'%s');
         exe=strfind(tasks,'.EXE');
         console=strfind(tasks,'Console');
         pid_after=zeros(1,size(exe,2));
        for i=1:1:size(exe,2)
            pid_after(1,i)=str2doubles(tasks((exe(i)+4):(console(i)-1)));    
        end
        if size(pid_after,2)>size(pid_before,2)
            command=['taskkill /f /PID ',mat2str(pid_after(1,end))];
            system(command)
        end

and got this error:

Undefined function 'str2doubles' for input arguments of type 'char'.

Error in indicatorsOUTblack2 (line 10)
          pid_before(1,i)=str2doubles(tasks((exe(i)+4):(console(i)-1)));

[Walter Roberson]

str2double not str2doubles

[Dima]

greta - this seems to work:

[~,tasks] = system('tasklist/fi "imagename eq Excel.exe"');
   tasks=sscanf(tasks,'%s');
   exe=strfind(tasks,'.EXE');
   console=strfind(tasks,'Console');
   pid_before=zeros(1,size(exe,2));
      for i=1:1:size(exe,2)
          pid_before(1,i)=str2double(tasks((exe(i)+4):(console(i)-1)));    
      end
      
      
[Num,Txt,Raw]=xlsread('test-BB.xls'); %'test','A1:FA2000','basic');

         [~,tasks] = system('tasklist/fi "imagename eq Excel.exe"');
         tasks=sscanf(tasks,'%s');
         exe=strfind(tasks,'.EXE');
         console=strfind(tasks,'Console');
         pid_after=zeros(1,size(exe,2));
        for i=1:1:size(exe,2)
            pid_after(1,i)=str2double(tasks((exe(i)+4):(console(i)-1)));    
        end
        if size(pid_after,2)>size(pid_before,2)
            command=['taskkill /f /PID ',mat2str(pid_after(1,end))];
            system(command)
        end

I need to ask one thing - after the above code I have a lot of lines of code - does closing the excel - after it has been used to read in the data - in any way affect the operation of the remining code? I guess the data is loaded into matlab and then excel can be killed safely?

Answer 3

[ybshokouhi]

I think this post requires an update. 'taskkill' is not recognized as an internal or external command, operable program or batch file.

[Walter Roberson]

taskkill is MS Windows only, and has existed since at least XP days. The Question itself is MS Windows specific as ActiveX is never used for Mac or Linux.

[Dima]

can this code be adapted to kill the last excel processes? or it is uselss

[Jan]

@Dima: What exactly is "this" code and what is "the last" Excel process?

[Guillaume]

As per the first sentence in the answer, the issue discussed in the question has not been an issue since R2015b. In fact, killing the excel process is a bad idea particularly if you plan to open more excel files (you'll slow down the opening of these files). In general, unless you know what you're doing you shouldn't be killing excel processes.

I suspect that this code refers to Daniel's code. You could indeed adapt it to kill the last of the excel processes in the list. Whether that's the last one started or the one you intended to kill is not guaranteed.

[Dima]

thank you for your kind replies. I was referrign to this code:

system('taskkill /F /IM EXCEL.EXE');

I tried it and it just kills all Excel processes - I wonder if there is a way to kill each of the excel instances opened by Matlab (for some reason it fails to close them after being invoked via a macro and excel link). Our organisation uses 2011 version - cannot upgrade now.

[Jan]

@Dima: You can get the list of PIDs of the running Excel instances before Matlab opens it and afterwards. Then you can kill only the new instance. See Daniel's answer (link).

[Dima]

I tried this cose and it does nto seem to work - hwo can I troubel shoot it?

[Guillaume]

Why are you hell bent on killing excel processes? Do they affect you in any way?

[Dima]

yes - not hell bent but they add up - each lopp opens 5 instances and I have 168 loops!

[Walter Roberson]

Have you tried https://www.mathworks.com/matlabcentral/fileexchange/22365-function-for-faster-data-transfer-matlab-excel

Answer 4

[Scott]

I'll tell you why I am hell bent to so speak on killing the Excel processes--because every time I read in Excel in MATLAB, then open some other Excel spreadsheet outside of MATLAB, if I make changes in the other Excel spreadsheet, and I forget to save that other Excel spreadsheet, Excel does not ask me if I want to save changes, and thus the modifications are LOST. I've lost tons of Excel file mods because I can't stop the Excel process that MATLAB opens. All I need is a simple command to shut down the Excel process that MATLAB opens once I am done reading in the data. I am tired of losing data.

[Guillaume]

Which version of excel would that be?

For me, the excel process that matlab opens is a completely separate process than the one that gets created if I start excel outside matlab. So, I end up with two processes, the interactive excel, and the matlab one. Note that this is something that matlab has no control over. This is solely controlled by excel. The two processes being independent, what matlab does with its own process cannot have any effect on the interactive one.

Excel does not ask me if I want to save changes

This will happen if you forcefully terminate the excel process (e.g. with taskkill), since forcefully terminating a process will not let it do its normal shutdown tasks. Hence, if you leave the processes alone, this should not happen.

Answer 5

[Scott]

Excel 2010.

Answer 6

[Charper]

I want to chime in and add some useful information since this appeared on Google and helped me solve my problem.

We're using MATLAB + Jenkins in a Windows evnvironment and found that MATLAB leaves "zombie" Excel processes hanging around. After building up for a few days, this caused all kinds of weird effects, ranging from "insufficient memory resources" in Java and other processes despite having tons of free RAM, MATLAB just 'stalling' without doing anything, and even failing system() calls.

Solution - we ran the following batch commands both before and after the Jenkins command-line Matlab operation:

taskkill /F /IM EXCEL.EXE
EXIT /B 0

The 'taskkill' was as suggested here. However, it returns a positive error code. The 'exit' command returns a zero from the batch command so that Jenkins does not mark the build as failed if no Excel processes are stuck.

Answer 7

[Scott]

I don't know what "Jenkins" is...but "taskkill" is not a valid MATLAB function in the basic license. However, !taskkill /F /IM EXCEL.EXE does work. Just put an exclamation point in front, the command is recognized, and the Microsoft Excel process gets dumped in the Task Manager.