InDesign CC 2015 crashes on launch - How can I fix it?

Hi, hope someone can help me with this problem.

I'm running InDesign CC 2015 on Mac OS X Yosemite 10.10.5, but it has started crashing on launch (I'm also running CC 2017 but have no problem with this. I need 2015 for one client, 2017 for others).

Here's the crash report. What do I need to do to fix this problem? Thanks in advance for any help.

Process:               Adobe InDesign CC 2015 [417]

Path:                  /Applications/Adobe InDesign CC 2015/Adobe InDesign CC 2015.app/Contents/MacOS/Adobe InDesign CC 2015

Identifier:            com.adobe.InDesign

Version:               11.4.1.102 (11410)

Code Type:             X86-64 (Native)

Parent Process:        ??? [1]

Responsible:           Adobe InDesign CC 2015 [417]

User ID:               501

Date/Time:             2017-08-30 09:10:04.830 +0100

OS Version:            Mac OS X 10.10.5 (14F2511)

Report Version:        11

Anonymous UUID:        51FDD704-356E-52E5-009B-CD64B36A4088

Time Awake Since Boot: 150 seconds

Crashed Thread:        0  Main Thread  Dispatch queue: com.apple.main-thread

Exception Type:        EXC_CRASH (SIGABRT)

Exception Codes:       0x0000000000000000, 0x0000000000000000

Application Specific Information:

terminating

abort() called

Thread 0 Crashed:: Main Thread  Dispatch queue: com.apple.main-thread

0   libsystem_kernel.dylib         0x00007fff8c07f286 __pthread_kill + 10

1   libsystem_c.dylib             0x00007fff8fa199a3 abort + 129

2   libc++abi.dylib               0x00007fff8591f2d1 abort_message + 257

3   libc++abi.dylib               0x00007fff859478f4 default_terminate_handler() + 46

4   libc++abi.dylib               0x00007fff859450a1 std::__terminate(void (*)()) + 8

5   libc++abi.dylib               0x00007fff8594512e std::terminate() + 78

6   libc++abi.dylib               0x00007fff85944d55 __cxa_rethrow + 104

7   com.adobe.InDesign.Application UI 0x0000000115930579 0x1157ad000 + 1586553

8   com.adobe.dvacore.framework   0x0000000106c125e0 dvacore::config::ThrowError(dvacore::config::ErrorLevel, char const*, unsigned int, int, bool, dvacore::config::ReplacementValue const&, dvacore::config::ReplacementValue const&, dvacore::config::ReplacementValue const&, dvacore::config::ReplacementValue const&) + 80

9   com.adobe.dvaui.framework     0x00000001073926bd dvaui::utility::OS_ResourceManager::GetBinary(std::basic_string<unsigned short, std::char_traits<unsigned short>, std::allocator<unsigned short> > const&, std::basic_string<unsigned short, std::char_traits<unsigned short>, std::allocator<unsigned short> > const&, std::vector<char, std::allocator<char> >*) const + 173

10  com.adobe.exo.framework       0x000000010923e953 exo::app::AppBase::InitThemeEditorFromResource(std::basic_string<unsigned short, std::char_traits<unsigned short>, std::allocator<unsigned short> > const&, float, bool) + 99

11  com.adobe.exo.framework       0x000000010923f761 exo::app::AppBase::LoadDefaultTheme(exo::app::AppInitArgs&) + 49

12  com.adobe.exo.framework       0x000000010923df94 exo::app::AppBase::Initialize(exo::app::AppInitArgs&) + 820

13  com.adobe.InDesign.Application UI 0x000000011593df37 0x1157ad000 + 1642295

14  com.adobe.InDesign.AppFramework 0x00000001156d019c 0x11557e000 + 1384860

15  com.adobe.InDesign.AppFramework 0x00000001156d066e 0x11557e000 + 1386094

16  com.adobe.InDesign             0x000000010653b68d main + 285

17  libdyld.dylib                 0x00007fff846be5c9 start + 1

[snipped by moderator]