Error message after adding file-base TM

Question

Any idea what this error message means:

Oana Nagy · Answer

Hello Frank Van T Veer , 
 Furthermore, to your previous thread- 
 https://community.sdl.com/product-groups/translationproductivity/f/studio/26678/error-message-this-method-property-must-be-called-on-the-ui-thread-etc-etc 
 The only cases we have ever seen of this have been resolved by simply closing Studio and rebooting your machine. 
 We have seen so few cases of this that we do not know what causes this.

Trados Studio > 1. Trados Studio

Error message after adding file-base TM