Node export was unable to recognize the format of the supplied code. No nodes imported.

Not sure what the problem is exactly.

A safe bet on getting it to work is to disable all the format modules (node_export_csv, node_export_serialize, node_export_xml) on both sites.

Then just use the default to export.

If that fails, perhaps something is going wrong during the copy-paste, and you should use the file download/upload method instead?

The other possibility is that different modules are enabled on the two sites causing a compatibility issue. This is certainly true of the modules within the node export package, but possibly others too.

Reopen if you require more assistance regarding this, or can narrow down the problem further.

I recently got this message as well.
I tried importing via "Upload file" as well as "Paste code". The only thing I noticed were that 2 of the nodes I was importing were different content types as the other nodes. After I excluded those nodes from the export, I was able to import them.
Not sure if that was the real issue though.

I also just received this error message, using defaults throughout, to export a particular content type.

Turns out I was trying to import a "Feature" I had created, a tar file, rather than a .export file.

I ran into this as well. Turning off all sub modules except CSV sorted it for me.

I ran into this as well. For me, this was only occuring when I tried to import content types with image fields. The major problem was that I had not enabled file attachments to be exported with the nodes. The form is very clear, but I just didn't realize I needed to turn this on. I now have it working with drupal 7.15 using the node_export_features submodule without problems.

To enable files to be sent with the node:
1) Login as admin on the source server (where the nodes are now)
2) Go to /admin/config/content/node_export
3) Scroll down most of the page to the "File fields" box.
4) Check the box next to each content type you want to export which has images
5) Save
6) Login as admin to the destination server (where you want the nodes to be imported)
7) Repeat steps 2 - 5 on this server
8) Make sure that all settings on the source and destination server are the same.
9) Save

This process seemed to fix the issue for me.

I had this same error with the dsv format. Just for kicks, I did a node-export-export and then, without modification, tried a node-export-import of the freshly exported csv file. Same error message, both using drush or the "paste" UI option.

This happened to me when importing into D7.20 from D7.0, both using the same version of node_export 7.x-30. I had defaults set on both sites. I ended up getting it to work by exporting as XML.

Thanks brycefisherfleig - this saved me.

Glad to see it is being worked on. I just want to export/import between versions of a development site. For me, opening the node-export file and deleting the initial error messages allowed me to successfully export-import the file between sites. Would be nice if the error messages appeared someplace other than the export file - like in the export form page - since it seems to be formatted for html anyway. This is the initial set of error messages pasted here and shown without the html tags:

Notice: Undefined variable: nids in /home/ ... /sites/all/modules/node_export/node_export.pages.inc on line 332

Notice: Undefined variable: code_string in /home/ ... /sites/all/modules/node_export/node_export.pages.inc on line 332

Warning: implode(): Invalid arguments passed in /home/ ... /sites/all/modules/node_export/node_export.pages.inc on line 440

Notice: Undefined index: in /home/ ... /sites/all/modules/node_export/node_export.pages.inc on line 447

fixing typo

1)I have Exported basic page content using feature module in Drupal 7.27 version.
2)Try to enable feature module in another Drupal instance having same version after enabling feature exported module its giving as below error
Notice: unserialize(): Error at offset 4343 of 355561 bytes in node_export_serialize_import() (line 23 of D:\Users\xxx\xampp\htdocs\xxx_feature\sites\all\modules\contrib\node_export\formats\serialize.inc).
Node export was unable to recognize the format of the supplied code. No nodes imported.

On the off-hand chance I'm not the only person stumbling into an issue with Drupal 6 node export (and I can save someone the resulting 2-3 minutes of head-scratching): I had Devel turned on and it was adding memory usage material at the end of the exported file. Turned off Devel. Worked like a charm.

I'm getting this error too, but in light of the last few comments I've tried on multiple drush versions (6.0.0, 7.0.0, 8.0.0) with no change.
Devel has been disabled in these cases, and the same problem exists when trying through Drupal's GUI.

I intend on trying a couple more things, so if I manage to get around it I'll tell you all.

I got same issue but when i check configuration i got both site have different format and File export mode when i set format "Drupal var export" and File export mode " Inline Base64" for both site issue resolve for me and able to import node successfully.

I got the same error. I had a look at the exported file: it contained an array with the exported content and... some HTML formatted message from the devel module. I manually removed the HTML and it worked.