Ember js 'ember build' error - Error: EBUSY: resource busy or locked, symlink

I have a existing quiet old ember.js project which I want to edit/mod. When running 'ember build' or 'ember serve' I get the error below. I read the other issues similar to this but none of the suggestion helped me so far. Can anyone please help how to solve this?

Output from ember version --verbose && npm --version: ember-cli: 2.5.1 http_parser: 2.7.0 node: 5.12.0 v8: 4.6.85.32 uv: 1.8.0 zlib: 1.2.8 ares: 1.10.1-DEV icu: 56.1 modules: 47 openssl: 1.0.2h os: win32 x64

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Build failed.
The Broccoli Plugin: [BroccoliMergeTrees: Addon#treeFor (ember-data - addon)] fa
iled with:
Error: EBUSY: resource busy or locked, symlink 'C:\myprojectfolder\tmp\broccoli_merge_trees-output_path-z7GLec0z.tmp' -> 
'C:\myprojectfolder\tmp\broccoli_merge_trees-input_base_path-dgyw33ia.tmp\4'
    at Error (native)
    at Object.fs.symlinkSync (fs.js:945:18)
    at symlinkWindows (C:\myprojectfolder\node_modules\symlink-or-copy\index.js:123:18)
    at symlinkOrCopySync (C:\myprojectfolder\node_modules\symlink-or-copy\index.js:63:5)
    at C:\myprojectfolder\node_modules\broccoli-plugin\read_compat.js:86:11
    at tryCatch (C:\myprojectfolder\node_modules\rsvp\dist\rsvp.js:525:12)
    at invokeCallback (C:\myprojectfolder\node_modules\rsvp\dist\rsvp.js:538:13)
    at publish (C:\myprojectfolder\node_modules\rsvp\dist\rsvp.js:508:7)
    at flush (C:\myprojectfolder\node_modules\rsvp\dist\rsvp.js:2415:5)
    at _combinedTickCallback (internal/process/next_tick.js:67:7)

The broccoli plugin was instantiated at:
    at BroccoliMergeTrees.Plugin (C:\myprojectfolder\node_modules\broccoli-plugin\index.js:7:31)
    at new BroccoliMergeTrees (C:\myprojectfolder\node_modules\broccoli-merge-trees\index.js:42:10)
    at BroccoliMergeTrees (C:\myprojectfolder\node_modules\broccoli-merge-trees\index.js:36:53)
    at mergeTrees (C:\myprojectfolder\node_modules\ember-cli\lib\models\addon.js:35:14)
    at Class.treeFor (C:\myprojectfolder\node_modules\ember-cli\lib\models\addon.js:300:10)
    at C:\myprojectfolder\node_modules\ember-cli\lib\broccoli\ember-app.js:463:20
    at Array.map (native)
    at EmberApp.addonTreesFor (C:\myprojectfolder\node_modules\ember-cli\lib\broccoli\ember-app.js:461:30)
    at EmberApp._addonTree (C:\myprojectfolder\node_modules\ember-cli\lib\broccoli\ember-app.js:871:36)
    at EmberApp._processedVendorTree (C:\myprojectfolder\node_modules\ember-cli\lib\broccoli\ember-app.js:916:20)