I have an external library which works fine for LTspice IV. To add this external library, I simply overwrote (added) the corresponding files in the lib folder in the installation directory. Hence, I have a lib folder of the following structure:

  - cmp
  - sub
  - sym

When I do the same in LTspice XVII, it doesn't work. This means, that if I open a schematics which uses myPart the error message "Couldn't find symbol(s): myPart" pops up. I also can't find this part in the "Component browser" in LTspice XVII but it is available in LTspice VI.

How can I add this library in the XVII version?

  • \$\begingroup\$ XVII uses custom paths, you should make use of them, otherwise you may run into problems when you'll want to send the schematic to someone else. The best way, but the most cumbersome, would be to copy both library(s) and symbol(s) to whatever folder your schematic/project/etc resides in. \$\endgroup\$ Commented Jan 8, 2020 at 20:57

1 Answer 1


I'm only 75% sure that this is the problem, but it's the problem I had when I moved to the new LT spice.

LT spice uses a new directory, stored in documents\LTspiceXVII\lib (not in C:\program files\lt spice\lib).

Make sure you modify the files there and not in the program directory which has a dual structure, but LT spice uses the files stored in documents folder.

  • \$\begingroup\$ Yes, this solved the problem. Thank you very much! \$\endgroup\$
    – Steradiant
    Commented Jan 6, 2020 at 19:11

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