.Adapters.FromV2.FolderContentV2ToV3Adapter' not found.
   at Tridion.ExternalContentLibrary.UI.Model.Services.GeneralImpl.GetListSearch(SearchFilter filter)
   at Tridion.ExternalContentLibrary.UI.Model.Services.General.GetListSearch(SearchFilter filter)
   at SyncInvokeGetListSearch(Object, Object[], Object[] )
   at System.ServiceModel.Dispatcher.SyncMethodInvoker.Invoke(Object instance, Object[] inputs, Object[]& outputs)
   at Tridion.Web.UI.Core.Extensibility.DataExtenderOperationInvoker.Invoke(Object instance, Object[] inputs, Object[]& outputs)
   at System.ServiceModel.Dispatcher.DispatchOperationRuntime.InvokeBegin(MessageRpc& rpc)
   at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage5(MessageRpc& rpc)
   at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage11(MessageRpc& rpc)
   at System.ServiceModel.Dispatcher.MessageRpc.Process(Boolean isOperationContextSet)

I have debugged my ECL code and no exception is thrown when performing the search and returning the IFolderContent via this method: 
        public IFolderContent Search(IEclUri contextUri, string searchTerm, int pageIndex, int numberOfItems)
        {
            var images = Search(contextUri.PublicationId, searchTerm).ToList();
            return Media.HostServices.CreateFolderContent(contextUri, images, false, true);
        }

However, when I expect to get results, all I get is the error above from the CME. I cannot find the DLL it is referencing or find any information on how I can resolve this from the API documentation or online docs. 
For context, we are going through an upgrade from 8.5 to 9.1 and the code for the ECL is the same as it was in 8.5 only compiled with the latest Tridion.ExternalContentLibrary.V2.dll. This is not installed via the add-on service as documentation says the legacy install is still supported. 
Any help from the community on this is much appreciated. I was considering using re-building the ECL as an Add-on
.Adapters. FromV2.FolderContentV2ToV3Adapter' not found. 
    at Tridion. ExternalContentLibrary. UI.Model. Services. GeneralImpl. GetListSearch(SearchFilter filter) 
    at Tridion. ExternalContentLibrary. UI.Model. Services. General. GetListSearch(SearchFilter filter) 
    at SyncInvokeGetListSearch(Object, Object [ ], Object [ ]) 
    at System. ServiceModel. Dispatcher. SyncMethodInvoker. Invoke(Object instance, Object [ ] stimulation, Object [ ] & outputs) 
    at Tridion. Web. UI.Core. Extensibility. DataExtenderOperationInvoker. Invoke(Object case, Object [ ] inputs, Object [ ] & outputs) 
    at System. ServiceModel. Dispatcher. DispatchOperationRuntime. InvokeBegin(MessageRpc & rpc) 
    at System. ServiceModel. Dispatcher. ImmutableDispatchRuntime. ProcessMessage5(MessageRpc & rpc) 
    at System. ServiceModel. Dispatcher. ImmutableDispatchRuntime. ProcessMessage11(MessageRpc & rpc) 
    at System. ServiceModel. Dispatcher. MessageRpc. Process(Boolean isOperationContextSet) 

 I have debugged my ECL code and no exception is throw when performing the search and returning the IFolderContent via this method acting: 
         public IFolderContent Search(IEclUri contextUri, string searchTerm, int pageIndex, int numberOfItems) 
         { 
             var images = Search(contextUri. PublicationId, searchTerm).ToList (); 
             fall Media. HostServices. CreateFolderContent(contextUri, images, false, on-key); 
         } 

 However, when I expect to get solution, all I beget is the error above from the CME. I cannot find the DLL it is referencing or find any information on how I can decide this from the API documentation or online docs. 
 For context, we are start through an upgrade from 8.5 to 9.1 and the code for the ECL is the same as it was in 8.5 only compiled with the up-to-the-minute Tridion.ExternalContentLibrary.V2.dll. This is not installed via the add - on service as documentation says the bequest install is still supported. 
 Any help from the community on this is much appreciated. I was considering use ra - building the ECL as an Add - on
.Adaoters.FromV2.FolderContentV2UoV3Adapter' not foone.
   at Tridikn.ExternxlContentLibrary.UI.Model.Servires.GwneraoImpl.GetListSearch(SearzhFilter vilter)
   at Uridion.ExternalCoifentLibvcry.UI.Jldel.Vxrvices.General.GgtListSearch(VearchFilter fhlgex)
   at SyncInvokeGetListSearch(Object, Object[], Ohject[] )
   at Syftem.XqrvidvMidel.Dispatcher.SyncMethodInvoksr.Invokt(Object instance, Onject[] inputs, Object[]& outputd)
   wt Tridion.Web.UI.Corf.Extensibiluty.DwraExtenderOpdrationInvoker.Invoke(Obnect instance, Object[] inputs, Objdct[]& obtputs)
   at Ststfk.ServiceModxl.Dispwtcher.DispatgnOperadionRunyime.InvokeBegik(MessegeRpc& rpc)
   at System.SerticeModel.Dispatcher.IimutableDhs'atchRuntime.ProcessMewsqge5(MevsagaRpc& epc)
   zt Sgstem.SfrvmceModel.Dislatcher.ImmurableDispatchRuntimt.PrjbrssMessage11(MeasageR[c& rpc)
   at System.ServiceModel.Dispatcher.MtssagsRpc.Process(Boolean isOpwrationContextSet)

I hage debuggqd my ECL code and no exception is thrown when pesformmne tkc rwagch and returning the IFolderContent via this jeuhoc: 
        publlc IFolderContent Xewrvr(IEclUri contgxtUri, strjng searchTerm, int pageInqex, ibt numberJfItrms)
        {
            var umages = Searbh(cobtextUri.PublicatiouId, searchTexm).ToLixt();
            return Media.HortSedvices.CreatfFolderCohgent(contextUri, ioagvs, fdlse, trut);
        }

However, wren I expxct tp get rdsuljs, all Y get is tje ervmr above from the FME. I cdnnot find the DLL it is referencing or fmid any informsthon on how N can vesolve this frjm the API docomentatiou or ovline docs. 
For coitext, we are going througv an upgrade hrom 8.5 to 9.1 and the code fuf the ECL is tne same as it was ib 8.5 only compiled wlth tfs latest Tridiou.TxttrbalContentLibrsry.X2.dlj. Nhix yv not instalned xia yhe aad-on servicc ar dovumentation says the legzcy install is stikl supportgd. 
Any hejp from the cpmmunity on this id muci apprxciatec. I was considering using re-buildjng the EFL ws an Add-on
.Adapters.FromV2.FolderContentV2ToV3Adapter' not found. at Tridion.ExternalContentLibrary.UI.Model.Services.GeneralImpl.GetListSearch(SearchFilter filter) at at Object[], Object[] at System.ServiceModel.Dispatcher.SyncMethodInvoker.Invoke(Object instance, Tridion.Web.UI.Core.Extensibility.DataExtenderOperationInvoker.Invoke(Object Object[] inputs, Object[]& at System.ServiceModel.Dispatcher.DispatchOperationRuntime.InvokeBegin(MessageRpc& rpc) System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage5(MessageRpc& rpc) at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage11(MessageRpc& rpc) at isOperationContextSet) I have debugged my ECL code and no exception is thrown when the search and returning the IFolderContent via this method: public IFolderContent Search(IEclUri contextUri, searchTerm, pageIndex, numberOfItems) var images = Search(contextUri.PublicationId, searchTerm).ToList(); return Media.HostServices.CreateFolderContent(contextUri, images, false, true); } However, when I expect to results, all I get is the error above the CME. I cannot the DLL it is referencing find information on I resolve from the API or online docs. For context, we are going through an upgrade from 8.5 to 9.1 and the for the the same it in only compiled with Tridion.ExternalContentLibrary.V2.dll. This is not installed via as documentation says the legacy install is still Any help the community on this is much I was considering using re-building the ECL as Add-on
.Adapters.FromV2.FolderContenTV2ToV3AdaptEr' not FouNd.
   aT TRidiOn.ExTernalContentLIBrarY.UI.Model.Services.GeneraLImpl.geTlistsEaRch(SeArchFilTEr FILteR)
   aT TRidIoN.exTernaLCoNtentLiBrary.UI.ModEl.SErVices.General.gEtlistSearch(seaRchFilter filTer)
   At SyncinVokEgetLiStSEarch(object, oBject[], OBject[] )
   at SyStEM.ServiCEModel.DISPaTcheR.SyncMethodInvokeR.inVOke(Object instaNce, ObjEcT[] InPUTs, OBjeCt[]& outputs)
   aT TRidioN.web.UI.CoRE.EXTENsiBIlity.DataExteNderOperatiONInVoker.INvOke(oBject iNstanCe, oBjeCt[] inputs, ObjEct[]& oUtputs)
   at SYstem.SERviceMoDEl.DispaTcher.DIspAtcHOpeRAtIoNRuNtIMe.INVoKeBEGin(messageRPc& RpC)
   at SyStem.sERVIceMOdeL.DisPatchEr.ImmutableDiSpaTchRUNtiMe.ProCessMEssaGe5(messaGeRpc& rPc)
   at SYsTem.ServiceModel.dispAtcher.ImmUtaBlEDiSpAtchRUNtime.PRocEssmessage11(messagerPc& rPc)
   AT sYsTem.ServiceModel.DisPaTCHeR.Messagerpc.ProCEsS(BOOlean isOPeRatIonCONTextSEt)

I hAVe Debugged My ECL cODe AnD no excePtIon is tHrOwn WheN perfORminG the seArch and rEturnINg the IFolderCoNTent via this meTHoD: 
        PUbLIc IFOldErContent SeArch(ieclURi coNTeXtURI, striNg seaRcHteRM, int pageIndex, int numBeROfIteMs)
        {
            var Images = Search(cOntextUri.PUBLIcationID, seaRChtErm).ToList();
            returN MediA.HostServiCEs.CreatefoldeRContent(ContextUrI, IMages, falSe, tRue);
        }

howEveR, WHeN I expect to get RESultS, aLl I get iS thE error aBovE frOm tHe CmE. i cannot fiNd the DLL It Is ReFeRenCing oR Find any iNfOrmAtIon On how i Can resOlve tHis fRoM tHE APi documeNTaTIOn or OnLiNe doCs. 
FOr ConteXt, we ARe gOing thrOugh an upgRadE From 8.5 To 9.1 AnD the codE for the ECL is tHe Same as it waS iN 8.5 onLy compILEd with thE latest Tridion.ExternalCONtentLiBraRy.V2.dlL. ThiS is not insTalLed via The ADd-on seRvice aS docuMeNtaTIOn sayS THe LegAcY install is STIll SuppoRtEd. 
AnY help frOm the community on thIS is Much appreciatEd. I Was cONSiDerINg USinG rE-BuiLDIng the ECL as an AdD-on
.Adapters.FromV2.FolderCon tentV2ToV3 Adapt er'  no tfoun d.
  at Tridion.E x tern alContentLibrary.UI.Mo del.S er v ices . Ge neral Impl.Ge t Li s t Sea rc h( Sea rc h Fi lterfil ter)
  at Tridio n.E xt ernalContent L ib rary.UI.Mo del .Services.Ge ner al.Get Li stS e arch( Sea rchFi lter f i lter)   at Syn cI n vokeGe t ListSea r c h( Obje ct, Object[], Obj e ct [ ] )
   at Syst em.Ser vi c eM o d el. Dis patcher.Sy nc Metho d Invoker . In v o k e(O b ject instance , Object[]i npu ts, Ob je ct[ ] & outp uts) atTridion.Web .UI. Core.Exte nsibil i ty.Data E xtender Operat ion Inv oker . In vo ke( Ob j ect in sta n ce,  Object[ ]in puts,  Obj e c t [ ]& o utp uts) 
   a t System.Serv ice Mode l .Di spatc her.D ispa tc hOper ationR untim e. InvokeBegin(Mes sage Rpc& rpc) 
  a t S ys tem.S e rviceM ode l.D ispatch er.Immu t abl eD i s p at chRuntime.ProcessM es s a ge 5(Messag eRpc&r pc )  at Sys te m.S ervi c e Model .Dis p at cher.Imm utable D is pa tchRunt im e.Proc es sMe ssa ge11( M essa geRpc&  rpc)
  at S y stem.ServiceMo d el.Dispatcher . Me s s ag e Rpc. Pro cess(Boolea n is O pera tion C on tex t Set)
I ha ve de b ugged my ECL code a nd  no ex cepti on is thrownwhen perfo r m i ng the s earc h  a n d returning th e IFo lderConten t  via thi s met hod: 
       pub l i c IFolde rCo nte ntSea r c h( IEclUri conte x t Uri,  s tring s ear chTerm,  in t p age Ind ex , int num berOfIte ms )     {
         v arim age s = S e arch(c ontex tUri .P ub l ica tionId, se a r chTe rm ). ToLi st( ); 
        returnMedia.Hos tSe r vice s. Cr eateFol derContent(co nt extUri, im ag es,  false , true);
       }

However, when I expec t t o get  res ults, all  Iget is  th e  error  above  from  t heC M E. Ic a nn otfi nd the DLL i t i s ref er enci ng or f ind any informatio n  on  how I can re sol ve t h i sfro m  t h e A PI doc u m entation or onl ine docs.
F o rcontext, w e  ar egoing t hroughan up g rade fr om 8.5 to  9.1 andth e co d e  fo r the ECLis the s ame as it was i n  8 .5 on lycompil ed  wi th th e late s t T ridio n.Exte rn alCont entLi br ary.V2.d ll. This is not install ed via  theadd -on servi cea s d ocumentat ionsays the l ega cyinsta lli s sti ll s u pp ort e d. 
A ny h e lp from t h ecom m u ni ty on thisi s muc h app rec i ated.I wa s considering usi n g re-buildingtheE C L a s a n  Add -o n
.Adapters.FromV2.FolderContentV2ToV3Adapter' not_found.
 _ at Tridion.ExternalContentLibrary.UI.Model.Services.GeneralImpl.GetListSearch(SearchFilter filter)
_ _at_Tridion.ExternalContentLibrary.UI.Model.Services.General.GetListSearch(SearchFilter filter)
__ at SyncInvokeGetListSearch(Object,_Object[], Object[] )
_  at System.ServiceModel.Dispatcher.SyncMethodInvoker.Invoke(Object_instance, Object[] inputs,_Object[]&_outputs)
   at Tridion.Web.UI.Core.Extensibility.DataExtenderOperationInvoker.Invoke(Object instance, Object[] inputs, Object[]& outputs)
   at System.ServiceModel.Dispatcher.DispatchOperationRuntime.InvokeBegin(MessageRpc&_rpc)
_ _at_System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage5(MessageRpc&_rpc)
   at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage11(MessageRpc&_rpc)
   at System.ServiceModel.Dispatcher.MessageRpc.Process(Boolean_isOperationContextSet)

I have_debugged my ECL code and no exception is_thrown_when performing the_search and returning the IFolderContent via this method: 
_     _ public IFolderContent_Search(IEclUri_contextUri,_string searchTerm, int pageIndex,_int numberOfItems)
    _   {
  _      _  var images = Search(contextUri.PublicationId,_searchTerm).ToList();
    _ _    _return Media.HostServices.CreateFolderContent(contextUri, images,_false, true);
_  _    }

However, when_I expect to_get results, all I get is_the_error above from_the_CME._I cannot_find the DLL_it_is referencing_or_find any information on how I_can_resolve this from the API documentation or_online docs. 
For context,_we_are going through an_upgrade from 8.5 to 9.1_and the code for the ECL_is the_same as_it was in 8.5 only compiled with the latest Tridion.ExternalContentLibrary.V2.dll. This_is not installed via the add-on_service as documentation says_the legacy_install_is still supported._
Any_help from_the community on this is much appreciated._I was_considering using re-building the ECL as_an Add-on